D: Mechanical Systems, section 3: developing simple machines Flashcards
1
Q
What is design?
A
It is the physical form of a device that makes it usable
2
Q
What is the church key opener?
A
A church key is a simple machine, a lever. It multiplies the force you use and focusses it to a tiny point
3
Q
What are the advantages to the church key?
A
It multiplies the force you use and focusses it to a single point
4
Q
What are the disadvantages to the church key?
A
It wasn’t built into the lid so you had to buy one
5
Q
What is the removable tab on cans?
A
A tab that was built correctly and was better for the consumer.
6
Q
What is function?
A
It is what a device is supposed to do
7
Q
What is work in scientific terms?
A
Work is a transfer of energy.
At this level, work is known as force times distance.
In later courses you’ll learn the following:
Work is the transfer of energy by a force acting on an object as it is displaced. The work W that a force F does on an object is the product of the magnitude F of the force, times the magnitude d of the displacement, times the cosine of the angle θ between them. In symbols, W = Fd cos θ.
This is because FCosθ is equal to the magnitude of the x component of the force. Or the component that is parallel to the displacement.
8
Q
What type of energy do the pedals of a bicycle have when they move?
A
Kinetic energy.
9
Q
What combination forms a wheel-and-axle machine on a bicycle?
A
Pedals and sprocket are parts of this simple machine.
10
Q
What is the final form of energy transferred throughout the bicycle?
A
Kinetic energy.
11
Q
From where does the energy for doing work on a machine come?
A
Chemical energy stored in food.
12
Q
What are two common sources of energy for machines?
A
- Fuels (e.g., gasoline)
- Electrical energy.
13
Q
What is stored energy also called?
A
Potential energy.
14
Q
What type of potential energy is stored in machines and the human body?
A
Chemical potential energy.
15
Q
What happens to the energy of a ball when it is lifted to a higher level?
A
It becomes gravitational potential energy.
16
Q
What type of stored energy does a ball have when it is lifted but not moving?
A
Gravitational potential energy.
17
Q
True or False: Energy can be created or destroyed.
A
False.
18
Q
What type of energy does a falling ball gain from gravity?
A
Kinetic energy.
19
Q
Fill in the blank: Stored energy is also called _______.
A
Potential energy.
20
Q
What practical systems store energy in the form of gravitational potential energy?
A
[Examples can vary, but common systems include dams, roller coasters, and elevated water tanks.]
21
Q
What does the fan belt transmit power from?
A
A car’s crankshaft
The fan belt transmits power to a fan that cools the radiator and to a pulley for the alternator.
22
Q
What is the primary function of the alternator in a car?
A
Produces electricity
The alternator generates electricity for use in the car or for storage in the battery.
23
Q
What percentage of efficiency do many car engines typically achieve?
A
About 20 percent
This indicates that a significant amount of energy is lost in car engines.
24
Q
What is energy transmission?
A
The transfer of energy from one place to another without changing it
Examples include a bicycle chain and electrical wires.
25
What are energy transmitters?
Devices that transfer energy without changing its form
## Footnote
Examples include a bicycle chain and electrical wires.
26
Is any machine 100 percent efficient?
No
## Footnote
Real machines always experience some energy loss.
27
How is the efficiency of a machine defined?
A comparison of useful work output to work input
## Footnote
Efficiency is usually expressed as a percentage.
28
What is the formula for calculating the efficiency of a lever?
Efficiency = (Work done by lever on load / Work done on lever by effort force) x 100%
## Footnote
This formula helps determine how well a lever transfers energy.
29
What happens to energy when a machine does work?
Some energy is lost due to friction
## Footnote
This loss can be understood through the equation: Work done on a machine = Work done by the machine + energy lost as heat due to friction.
30
True or False: A perfect machine would be 100 percent efficient.
True
## Footnote
However, real machines always have some efficiency less than 100 percent.
31
What can cause a machine's efficiency to decrease?
Friction
## Footnote
For example, rusty blades in hedge trimmers can increase friction.
32
What is one way to increase the efficiency of machines?
By reducing friction through lubrication such as oil or grease
## Footnote
Lubricants help to minimize wear and tear on machine parts.
33
What happens to lubricants over time?
They build up dirt and lose effectiveness
## Footnote
Dirty lubricants should be wiped off and replaced with clean grease or oil.
34
What is a gear?
A wheel with teeth along its circumference
## Footnote
Gears are modified wheel-and-axle machines.
35
How is the mechanical advantage of a pair of gears calculated?
By dividing the radius of the effort gear by the radius of the load gear
## Footnote
This calculation helps in understanding how gears amplify force.
36
What reduces the efficiency of a bicycle?
Friction between the pedal gear and the bicycle chain
## Footnote
Effort exerted must overcome this friction, leading to energy loss.
37
What can be done to boost the efficiency of a bicycle?
Regularly clean and lubricate the chain, gears, and moving parts, and keep tires properly inflated
## Footnote
These actions help reduce friction and improve performance.
38
What is the effect of properly inflated tires on vehicle efficiency?
It reduces friction between the road and the tires, leading to increased efficiency
## Footnote
Efficient vehicles provide better gas mileage and save energy.
39
Why is friction sometimes necessary for machines?
Friction is needed for proper functioning, such as preventing slipping
## Footnote
Without friction, bicycles and running shoes would not grip surfaces effectively.
40
How do baseball players and gymnasts use friction to their advantage?
They apply a powder called rosin to their hands to increase grip
## Footnote
Increased friction helps improve performance in sports.
41
What do curlers do to manage friction on the ice?
They sweep the ice to decrease friction, allowing the rock to travel farther and straighter
## Footnote
This technique is crucial for controlling the game in curling.
42
Fill in the blank: Many sports and outdoor activities utilize friction in a _______ way.
[useful]
## Footnote
Friction is critical for performance in various physical activities.
43
What can be inferred about poorly maintained bikes?
They increase the effort needed to ride due to higher friction
## Footnote
Maintenance is essential for optimal bike performance.
44
What is one activity you can do to explore efficiency and friction further?
Conduct an investigation on the effects of friction and lubrication on machine performance
## Footnote
Hands-on experiments can provide insight into these concepts.
45
What is the relationship between force, area, and pressure?
Pressure (p) is defined as the force (F) acting over a certain area (A)
## Footnote
The formula is p = F/A.
46
What happens to pressure when the area increases while keeping the force constant?
The pressure decreases
## Footnote
This is illustrated by the use of snowshoes, which increase the area and reduce pressure.
47
What is the formula for calculating pressure?
Pressure = Force / Area or p = F/A
## Footnote
This formula is essential for understanding how pressure is affected by changes in force or area.
48
In which units is force measured?
Newtons (N)
## Footnote
Force is a crucial component in calculating pressure.
49
In which units is area measured?
Square metres (m²)
## Footnote
Area is used in the pressure calculation formula.
50
What is the unit for pressure?
Newtons per square metre (N/m) or pascal (Pa)
## Footnote
1 kilopascal (kPa) is equal to 1000 pascals (Pa).
51
How does pressure relate to popping a balloon with a pin?
The pressure exerted by the pin is sufficient to overcome the internal pressure of the balloon
## Footnote
This demonstrates how pressure can change with force and area.
52
Fill in the blank: A kilopascal (kPa) is equal to _______.
1000 Pa
## Footnote
This conversion is important for understanding pressure measurements.
53
True or False: Increasing the area while keeping the force constant will increase pressure.
False
## Footnote
Increasing the area decreases pressure.
54
Why is it easier to slice food using a sharp knife rather than a dull one?
A sharp knife has a smaller area at the edge, which increases pressure
## Footnote
Higher pressure allows the knife to cut through food more effectively.
55
Why can a man lie on a bed of nails without injuring himself?
The force of the man's weight is spread over a larger area, reducing the pressure on any single point
## Footnote
Lying on a single nail would concentrate the force on a small area, causing more pain and potential injury.
56
What is the effect of spreading force over a larger area?
It lessens the force experienced at any single point, reducing the potential for injury
## Footnote
This principle applies in various scenarios, including sports and safety equipment.
57
What type of protective equipment do football players wear?
Helmets, chest protectors, and shoulder pads
## Footnote
These items help to distribute the force from tackles over a larger area.
58
What is the purpose of safety equipment such as helmets and shoulder pads?
To spread force over a larger area and lessen the impact of a blow
## Footnote
This reduces the risk of injury during contact sports.
59
Fill in the blank: Safety equipment is worn during in-line skating to reduce the _______.
potential for injury
60
True or False: Lying on a bed of nails is more painful than lying on a single nail.
False
61
What does Pascal's law state?
Pressure exerted on a contained fluid is transmitted undiminished in all directions throughout the fluid and perpendicular to the walls of the container.
62
Who first observed Pascal's law?
Blaise Pascal (1623-1662).
63
Does the shape of a container affect the pressure at any given depth according to Pascal's law?
No.
64
What is a hydraulic lift?
A mechanical system that raises heavy objects using fluid under pressure in a closed system.
65
What is an example of a closed hydraulic system in the human body?
The circulatory system.
66
What two types of cylinders are used in a hydraulic lift?
A small cylinder and a large cylinder.
67
What is the purpose of the hydraulic fluid in a hydraulic lift?
To transmit pressure.
68
Why is water not used as a hydraulic fluid in hydraulic lifts?
* It is not a good lubricant
* It can cause parts of a system to rust.
69
Fill in the blank: Pascal's law can be observed when you squeeze a _______.
water-filled balloon.
70
What does the hydraulic lift consist of?
A small cylinder, a large cylinder, and a pipe connecting them.
71
True or False: Every time you squeeze toothpaste, you are applying Pascal's law.
True.
72
What type of platform rests on the surface of the hydraulic fluid in a hydraulic lift?
A piston.
73
What is the primary function of a hydraulic lift?
To raise heavy objects.
74
What type of fluid is usually used in hydraulic systems?
Oil.
75
What is the formula for calculating pressure?
Pressure (p) is force (F) divided by area (A)
## Footnote
p = F / A
76
According to Pascal's law, how is pressure transmitted in a liquid?
Pressure is transmitted unchanged throughout the liquid
## Footnote
This means that any change in pressure applied to a confined fluid is transmitted equally in all directions.
77
What is the pressure applied to the large piston if the small piston has a pressure of 100 N/cm²?
100 N/cm²
## Footnote
Pascal's law states that the pressure remains the same throughout the fluid.
78
What is the area of the large piston in the example?
50 cm²
## Footnote
This is greater than the area of the small piston.
79
What is the total force on the large piston?
5000 N
## Footnote
Calculated as 100 N/cm² x 50 cm².
80
What is the relationship between the force applied to the small piston and the force on the large piston?
The total force on the large piston is ten times the force applied to the small piston
## Footnote
In this case, 5000 N is ten times 500 N.
81
What is the standard unit of pressure?
Pascal (Pa)
## Footnote
1 Pascal = 1 Newton per square meter.
82
Why are pressures often given in kilopascals (kPa)?
Because pascal is a small pressure unit
## Footnote
1 kPa = 1000 Pa.
83
What is a hydraulic lift used for?
To produce a large force on a load when a small effort force is exerted
## Footnote
It provides a mechanical advantage.
84
What mechanical advantage does a hydraulic lift provide?
A small effort force produces a large force on a load
## Footnote
This allows users to lift heavier loads than their own weight.
85
In the example, what force is applied to the small piston?
10 N
## Footnote
This generates a pressure of 10 N per unit of area.
86
How many unit areas does the large piston have in the example?
9 unit areas
## Footnote
Each unit area has the same area as the small piston.
87
What is the total force on the large piston when 10 N is applied to the small piston?
90 N
## Footnote
Calculated as 10 N x 9 unit areas.
88
What is the formula for mechanical advantage?
MA = Load force / Effort force
## Footnote
This formula calculates the mechanical advantage of a hydraulic lift.
89
What is the mechanical advantage of the hydraulic lift described?
9
## Footnote
The mechanical advantage indicates that the load is nine times greater than the effort force.
90
When using a hydraulic lift, how does the distance you push the piston compare to the distance the load is lifted?
You must push the piston nine times farther than the load is lifted
## Footnote
This is due to the conservation of work principle.
91
What is the formula for calculating work?
W = F • d
## Footnote
This formula states that work is the product of force and distance.
92
If you want to lift a 90 N load a distance of 2 m, how far do you need to push the piston?
18 m
## Footnote
This is calculated based on the work done being equal for both the effort and the load.
93
What is the work done on the load when lifting a 90 N load a distance of 2 m?
180 J
## Footnote
Work done on the load is calculated as W(load) = 90 N • 2 m.
94
Fill in the blank: To lift a load using a hydraulic lift, the work done on the small piston must be at least as great as the work done on the _______.
load
## Footnote
This ensures that the hydraulic system operates efficiently.
95
True or False: The effort distance is less than the load distance when using a hydraulic lift.
False
## Footnote
The effort distance is greater than the load distance in a hydraulic lift system.
96
What principle explains why mustard spreads over a larger area when squeezed from a container?
Pascal's law
## Footnote
Pascal's law states that pressure applied to a confined fluid is transmitted undiminished in all directions.
97
In the context of hydraulic systems, what does Pascal's law imply about pressure?
Pressure is transmitted equally throughout the fluid
## Footnote
This allows for force to be amplified in hydraulic systems.
98
What happens to the effort force when using a hydraulic system?
It is multiplied to lift a heavier load
## Footnote
This is achieved through the design of hydraulic systems that utilize different piston sizes.
99
What are the two essential characteristics of fluids used in hydraulic systems?
Incompressibility and ability to transmit pressure
## Footnote
These characteristics allow hydraulic systems to function effectively by using liquids in confined spaces.
100
What is an example of a hydraulic system mentioned?
Hydraulic lift
## Footnote
This example illustrates how hydraulic systems operate by using the force of a liquid.
101
How do pneumatic systems differ from hydraulic systems in terms of gas and fluid sealing?
Pneumatic systems do not seal gas in the same way hydraulic systems seal fluid
## Footnote
Pneumatic systems typically allow air to pass through under high pressure, unlike hydraulic systems that confine liquids.
102
What usually provides the high-pressure air in pneumatic systems?
A machine that draws in outside air and compresses it
## Footnote
This process is essential for the operation of pneumatic devices.
103
What happens to air in pneumatic systems when it passes through a device?
It escapes outside the device
## Footnote
This escape of air is a key characteristic of pneumatic systems.
104
Fill in the blank: Hydraulic systems apply the force of a _______ in a confined space.
[liquid]
105
Fill in the blank: Pneumatic devices typically use _______ under high pressure.
[air]
106
What tools are used in the hydraulically powered Jaws of Life?
Spreaders, rams, and cutters
## Footnote
These tools are crucial for rescuing accident victims from crushed vehicles.
107
True or False: Pneumatic systems seal gases similarly to how hydraulic systems seal liquids.
False
108
What is the primary function of inflatable walkways in pneumatic systems?
Help workers reach accident victims and carry them to safety
## Footnote
Inflatable walkways are effective examples of how pneumatic systems can be utilized in rescue operations.
109
What is the air pressure used in a jackhammer?
About 620,000 Pa
110
How much air flows through a jackhammer every minute?
More than 5.5 m
111
What is a common example of a pneumatic device?
Jackhammer
112
What is the function of the 'chuck' in a jackhammer?
Pounds rocks or concrete into fragments
113
In what applications are jackhammers commonly used?
Breaking up concrete, mining coal, nickel, and gold
114
What type of technology do modern dentists use for drilling?
Pneumatic instruments
115
What has the technology of pneumatic drills led to in dentistry?
Almost pain-free dentistry
116
What is the name of the newly invented machine that drills teeth with water?
Millennium
117
How does the Millennium device work?
Pumps a jet of water at the teeth, split by a laser into tiny particles
118
What advantage does the Millennium device provide compared to traditional drills?
No noise and less heat
119
Fill in the blank: The cutaway diagram of a dentist's drill shows that it relies on _______.
Pressurized air
120
True or False: Jackhammers produce a quiet sound when in use.
False
121
What does the term 'pneumatics' refer to?
Technology that uses compressed air
122
What are the components of a jackhammer as shown in the diagram?
Control lever, air inlet, diaphragm valve, piston, air outlet, cylinder, anvil, chuck
123
What is a significant benefit of using pneumatic instruments in dentistry?
Reduction of pain during procedures
124
What drives staples or nails into solid objects in staple guns and pneumatic nailers?
Pulses of air pressure
## Footnote
These tools are used in furniture making, woodworking, and upholstering.
125
What is the primary function of sandblasters?
To blast tiny sand particles out of a nozzle using high-pressure air
## Footnote
Sandblasting is effective for removing dirt and paint from surfaces like stone or brick.
126
What practical application does sandblasting serve for granite or marble stairs?
Increases friction to prevent slipping
## Footnote
Sandblasting roughens the edges of the stairs.
127
What type of cast has been developed by medical engineers that uses pressurized air?
Air cast
## Footnote
This cast has a solid frame with a balloon-like lining that can be adjusted for a snug fit.
128
Fill in the blank: Staple guns are used in _______.
making furniture, woodworking, upholstering
## Footnote
These applications highlight the versatility of staple guns.
129
True or False: Sandblasting can only be used for aesthetic purposes.
False
## Footnote
It also has practical applications, such as making stairs safer.
130
What happens to the cast when high-pressure air is pumped into its lining?
It fits snugly and securely to the injured leg
## Footnote
This allows for precise control over the fit of the cast.
131
List three applications of pneumatic devices mentioned in the text.
* Staple guns
* Pneumatic nailers
* Air casts
## Footnote
These devices demonstrate the use of air pressure in various fields.
132
What are the visual changes observed before and after sandblasting as shown in the figures?
Old, dirty surfaces are made to look new
## Footnote
This transformation applies to buildings and statues.
133
Fill in the blank: Sandblasting is an excellent way to remove _______ and _______ from stone or brick.
dirt, paint
## Footnote
This process is commonly used for cleaning surfaces.
134
What is the primary use of the Canadian Coast Guard hovercraft?
Rescue operations
## Footnote
Hovercraft are also used for transporting people, cars, and equipment.
135
What mechanism allows a hovercraft to float above water or land?
A 'skirt' holds in air to support the weight
## Footnote
The skirt retains enough air pressure to lift the craft.
136
How do hovercraft move forward?
Propellers drive the hovercraft forward
## Footnote
Rudders are used for steering.
137
Fill in the blank: In a hovercraft, powerful pumps draw in outside air and pump it out through holes in the _______.
bottom of the hovercraft
138
True or False: Hovercraft can support extremely heavy loads with enough air pressure.
True
139
What is the function of the lift fan in a hovercraft?
Sucks air into the hovercraft
## Footnote
This creates a cushion of air for support.
140
What does the cushion of air in a hovercraft do?
Supports the weight of the craft
## Footnote
It allows the hovercraft to glide over surfaces.
141
What is the primary function of hydraulic equipment?
To generate large forces for lifting or digging
## Footnote
Hydraulic equipment operates by using high-pressure fluids to perform work.
142
What type of engine typically powers hydraulic equipment?
Gasoline engine or electric motor
## Footnote
The energy for pumping hydraulic fluid is supplied by either of these engines.
143
What is the role of valves in hydraulic systems?
To direct high-pressure fluid through steel pipes
## Footnote
Valves ensure that the hydraulic fluid reaches the necessary parts of the machine.
144
Fill in the blank: Hydraulic machines contain tanks filled with _______.
hydraulic fluid
145
What are two systems in large machines that are often powered by hydraulic fluid?
Steering and braking systems
## Footnote
These systems utilize high-pressure hydraulic fluid to operate effectively.
146
True or False: Hydraulic systems in large machines are operated by manual plungers.
False
## Footnote
Large machines use pumps and hydraulic fluid, not manual plungers.
147
What is an example of hydraulic equipment mentioned in the text?
Bulldozer, backhoe, cherry picker, tractor
## Footnote
These machines utilize hydraulic systems for their operations.
148
How do hydraulic pumps generate pressure?
By using energy supplied by an engine or motor
## Footnote
The pumps create the necessary pressure to move hydraulic fluid.
149
Fill in the blank: The huge machines typically have _______ that generate pressure.
pumps
150
What is the significance of high-pressure hydraulic fluid in heavy equipment?
It generates large forces needed for operations
## Footnote
High-pressure fluid is crucial for effective lifting and digging.
151
What is the function of the nose wheel when an airplane taxis?
The pilot steers the plane using the nose wheel.
152
What does the pilot do to lower the aircraft's speed during the approach before landing?
The pilot uses hydraulics to lower the flaps and slats.
153
What prevents the wing from lifting the aircraft again when it touches down?
The spoilers.
154
Which control surfaces are adjusted by the pilot to make a turn while airborne?
Ailerons and rudder.
155
What is the purpose of the elevators during flight?
To keep the plane level.
156
How are the various parts of an airplane wing raised and lowered during landing?
Hydraulically.
157
What are the three separate hydraulic systems in an Airbus A340?
Green system, blue system, yellow system.
158
What happens if one hydraulic system malfunctions in an Airbus A340?
There are one or two other systems to back it up.
159
Which hydraulic systems control the flaps in an Airbus A340?
Green and yellow systems.
160
Which hydraulic systems control the slats in an Airbus A340?
Green and blue systems.
161
True or False: All three hydraulic systems in an Airbus A340 control the ailerons.
True.
162
Fill in the blank: The pilot uses hydraulics to raise the _______ when the aircraft touches down.
spoilers
163
What is the role of hydraulics in airplane control systems?
To power various mechanical systems such as flaps, slats, and ailerons.
164
What are slats used for during the landing process?
To slow the aircraft down.
165
How does the pilot adjust the airplane tail while airborne?
Using hydraulics.
166
What is the main purpose of the hydraulic systems in an aircraft?
To enable control of flight surfaces.
167
What does the green system rely on?
Fluid pressure generated by engines 1 and 4
168
What does the blue system rely on?
Fluid pressure generated by engine 2
169
What does the yellow system rely on?
Pressure from engine 3
170
What provides pressure for the hydraulic systems if an engine fails?
Additional backup motors
171
What happens if all hydraulic systems fail?
The pilot can still control the guidance systems
172
What device drops out from a door in the bottom of the plane during a hydraulic failure?
Emergency air-driven generator
173
What resembles a fan and generates alternative power for hydraulic systems?
Air-driven generator
174
What spins the propeller of the air-driven generator?
Outside air striking it
175
What is the outcome of the rapid turning motion of the air-driven generator's propeller?
Generates alternative power to supply the hydraulic systems
176
True or False: The air-driven generator produces both electricity and fluid pressure.
True
177
Fill in the blank: The green system relies on fluid pressure generated by engines 1 and _______.
4
178
Fill in the blank: The blue system relies on fluid pressure generated by _______.
engine 2
179
Fill in the blank: The yellow system relies on pressure from _______.
engine 3
180
What system in your body is described as a pneumatic system?
The respiratory system
## Footnote
The respiratory system includes lungs, tubes for air, and muscles for expansion and contraction.
181
How much air is drawn in during normal breathing?
About 500mL of air
## Footnote
This volume is inhaled when the muscles cause the lungs to expand.
182
How many times per minute do you breathe normally?
About 12 times per minute
183
What happens to your breathing rate during physical activity?
You breathe more quickly and more deeply
184
What type of system does your body depend on for blood circulation?
A hydraulic system
## Footnote
The hydraulic system is crucial for maintaining blood pressure and circulation.
185
What is the role of the heart in the hydraulic system?
The heart is the pump that moves blood through blood vessels
186
What is blood pressure?
The pressure exerted by blood against the inner walls of arteries and capillaries
187
How many times can the heart pump over a lifetime?
Nearly 4 billion times
188
How much fluid can the heart circulate throughout a lifetime?
Nearly 500 million litres of fluid
189
What happens to blood after it leaves the left ventricle?
It travels through arteries, then capillaries, and finally veins back to the heart
190
What is the diameter of the largest blood vessel in the body?
Just under 2 cm
191
What is the diameter of the smallest blood vessels, the capillaries?
Less than 0.0001 cm
192
Fill in the blank: It takes a great deal of pressure to push a fluid through tubes with small diameters, such as _______.
capillaries
193
If the blood vessels in your body were connected end to end, how far would they extend?
Almost 100,000 km
194
True or False: The total length of blood vessels in the body is equivalent to two and a half times around the Earth.
True
195
What happens when the pressure is reduced in one area of a fluid?
Fluid moves from the area of high pressure to the area of low pressure
## Footnote
Example: Releasing a closed balloon allows air to rush out due to pressure difference.
196
What is a valve?
A movable part that controls the flow of a fluid by opening or closing
## Footnote
Example: Your fingers act as a valve when holding a balloon closed.
197
How do manually operated valves function?
They are controlled by human intervention, such as turning a tap or holding a balloon
## Footnote
Example: The tap in a water pipe is a manually operated valve.
198
What is the role of automatic valves in pumps?
They operate using the pressure that the valve is controlling to move fluids in a specific direction
## Footnote
Example: Many pumps utilize automatic valves that open and close based on pressure changes.
199
How do valves in the large veins of the body operate?
They open when pressure from blood pushes against them and close to prevent backflow
## Footnote
This mechanism helps maintain unidirectional blood flow toward the heart.
200
What happens when skeletal muscles contract around veins?
They squeeze the veins, forcing blood to move forward under pressure
## Footnote
This action is crucial for venous return to the heart.
201
Fill in the blank: A valve is pushed open by pressure on one side and will close if the pressure becomes _______ on the other side.
[greater]
202
True or False: The pressure inside an inflated balloon is equal throughout the balloon.
True
203
What are the two main functions of the heart?
To circulate blood throughout the body
## Footnote
The heart acts as two pumps that manage blood flow through arteries and capillaries.
204
How many automatic valves does the heart use to circulate blood?
Four automatic valves
## Footnote
These valves play a crucial role in regulating blood flow.
205
What happens to blood pressure immediately after the heart contracts?
It causes high pressure in the arteries
## Footnote
This is a result of the surge of blood from the heart.
206
What occurs to blood pressure before the next heartbeat?
The pressure falls
## Footnote
This fluctuation is a normal part of the cardiac cycle.
207
What is the average heart rate of a human?
About 72 beats per minute
## Footnote
This rate can vary based on individual health and activity levels.
208
What is the role of the valves between the atria and ventricles during ventricular contraction?
They close
## Footnote
This prevents backflow of blood as it is forced into the arteries.
209
What happens to the valves between the atria and ventricles when the ventricles relax?
They open
## Footnote
This allows blood to flow from the atria into the ventricles.
210
Fill in the blank: Blood pressure _______ between heartbeats.
increases and decreases
## Footnote
This dynamic change is key to the heart's function.
211
True or False: The ventricles and atria contract simultaneously.
False
## Footnote
The ventricles contract after the atria, ensuring proper blood flow.
212
What is the effect of the ventricles contracting?
Forces blood into the arteries
## Footnote
This is essential for maintaining circulation throughout the body.
213
What forces blood into the body from the heart?
Left ventricle
## Footnote
The left ventricle pumps oxygenated blood to the body.
214
What is the function of the right atrium?
Receives deoxygenated blood from the body
## Footnote
This blood then moves to the right ventricle for pulmonary circulation.
215
What is the relationship between the contraction of the ventricle walls and blood flow?
Contraction forces blood out into the arteries
## Footnote
This action is crucial for effective blood circulation.
216
What is a simple machine?
A single lever, a pulley, or a wheel and axle.
217
What do we call a simple machine that is part of a larger system?
A subsystem.
218
How many simple machines can be combined to form modern machines?
Dozens or even hundreds.
219
What is an example of a subsystem that can be easily analyzed?
The braking system in a car.
220
What type of lever is the brake pedal subsystem classified as?
Class 2 lever.
221
In the braking system, what is the effort force?
The force of the driver's foot on the brake pedal.
222
What does the load represent in the brake pedal subsystem?
The force on a piston that applies pressure on the brake fluid.
223
What happens to the brake fluid when the driver pushes down harder on the brake pedal?
The effort force increases the pressure transmitted in the brake fluid.
224
Through what do the brake fluid flow from the master cylinder?
Tubes that branch out to every wheel.
225
What is the final action of the brake fluid at each wheel?
It exerts pressure on brake pads that press on a disc.
226
What physical principle is involved when the brake pads press on the disc?
Friction.
227
Fill in the blank: The friction between the brake pads and the disc ______ the car.
slows and eventually stops.
228
What is the function of a piston in a braking system?
The piston helps to transmit hydraulic pressure within the brake system
## Footnote
The piston is a crucial component that enables the transfer of force from the brake pedal to the brake pads.
229
What role does the master cylinder play in a braking system?
The master cylinder generates hydraulic pressure to activate the brakes
## Footnote
It is the main component that converts the mechanical force from the brake pedal into hydraulic pressure.
230
What is the purpose of the brake pedal?
The brake pedal is used by the driver to initiate braking
## Footnote
Pressing the brake pedal activates the braking system by creating pressure in the master cylinder.
231
What is the function of a wheel cylinder?
The wheel cylinder converts hydraulic pressure into mechanical force to apply the brakes at the wheels
## Footnote
It is essential for the operation of drum brakes.
232
What is a brake pad?
A brake pad is a component that creates friction against the brake disc to slow down or stop the vehicle
## Footnote
Brake pads are vital for disc brake systems.
233
What does the brake disc do?
The brake disc provides a surface for the brake pads to create friction
## Footnote
It is typically attached to the wheel and is crucial in disc brake systems.
234
What is brake fluid?
Brake fluid is a hydraulic fluid used to transmit force in the braking system
## Footnote
It is essential for the operation of hydraulic brakes.
235
Fill in the blank: The pressure of the driver's foot on a _______ is transmitted by fluid pressure to the wheels of the car.
brake pedal
## Footnote
The brake pedal is the initial point of force application in the braking system.
236
What is another name for a backhoe?
Excavator
237
What are the three levers in a backhoe called?
* Boom
* Dipper
* Bucket
238
What is the function of the slew ring in a backhoe?
It allows the rotating assembly of levers to swing around
239
What type of lever is the boom in a backhoe?
Class 3 lever
240
What type of lever is the dipper in a backhoe?
Class 1 lever
241
What type of lever is the bucket in a backhoe?
Class 1 lever
242
How does the boom function in relation to the dipper?
It raises or lowers the dipper
243
What hydraulic feature allows the bucket to be placed in any position?
The combination of the three levers powered by hydraulics
244
Fill in the blank: The assembly of levers in a backhoe is mounted on _______.
caterpillar tracks
245
True or False: The bucket in a backhoe can tilt to dig a hole.
True
246
What was the name of the locomotive that won a race in England in 1829?
Rocket
247
What speed did the Rocket achieve in its race?
47 km/h
248
In the nineteenth century, what speed did some people believe was dangerous for humans to travel?
20 km/h
249
Who was responsible for shovelling coal into the furnace of a steam locomotive?
Stoker
250
What does burning coal in a locomotive's furnace heat?
Water in the boiler
251
What gas is produced when water is boiled in a steam engine?
Steam
252
What principle is the motion of cars, trucks, and ocean liners based on?
The same scientific principles as the motion of a locomotive
253
What was the invention of the steam engine considered in the history of science and technology?
An important milestone
254
What fuels are commonly burned in a steam engine?
* Coal * Wood
255
What process occurs when water changes to steam in a steam engine?
Drives the engine
256
What major change occurred in production methods due to the invention of the steam engine?
Workers moved to large factories in cities
257
Fill in the blank: The motion of a locomotive is based on the same scientific principles as the motion of _______.
[cars, trucks, ocean liners, and many other vehicles]
258
True or False: We still commonly use steam locomotives today.
False
259
What did people use before the steam-powered engines became available for weaving cloth?
Looms in their own homes
260
What scientific principle does a hot-air balloon operate on?
Warm air rises
## Footnote
This principle led to the development of various mechanical devices.
261
Who developed the first practical steam engine and in what year?
Thomas Savery in 1699
## Footnote
Savery's steam engine utilized heated water to create steam.
262
What is a piston?
A movable disk or platform that fits inside a closed cylinder.
263
What happens when a piston moves?
It causes an attached rod to move.
264
Why did early steam engine inventors use steam instead of liquid water?
Steam expands significantly and can perform work.
265
What is the volume increase of 100 mL of water when it boils into steam at 100°C?
About 170,000 mL.
266
How many times does the volume of water increase when it turns into steam?
1700 times its original volume.
267
What happens to the volume of steam when heated to 200°C?
It expands to more than 200,000 mL.
268
Who was Hero of Alexandria?
A Greek engineer who described many mechanical devices around 150 B.C.E.
269
What types of systems did Hero's devices use?
Gears, wheels and axles, pulleys, hydraulics, and pneumatics.
270
Describe the operation of Hero's altar device.
A fire heated air in a sealed pedestal, increasing pressure and moving water.
271
Fill in the blank: The expansion of a liquid to a gas can be used to do _______.
work.
272
True or False: Steam engines were the first mechanical devices to run on steam.
False.
273
What innovation led to advancements in transportation?
The invention of steam engines
274
What was an important means of transportation in Canada from 1836 to 1957?
Steamboats
275
How many steamboats traveled along the rivers and coasts of British Columbia and the Yukon during their peak?
More than 3000
276
What did the steamboats carry between British Columbia and the Yukon?
Gold seekers
277
By what year were seventeen ships regularly traveling on the North Saskatchewan, South Saskatchewan, Assiniboine, and Red rivers?
By 1879
278
What materials did steamboats transport besides passengers?
Materials of the fur trade and farming equipment
279
Fill in the blank: Steam causes a paddle wheel to turn by _______ under high pressure.
expanding
280
What happens to the piston when steam flows into the right side of the cylinder?
It is pushed to the left
281
What opens to allow old, cooled steam to escape from the cylinder?
An exhaust valve
282
How does steam cause the piston to move back and forth?
Steam alternately enters each side of the cylinder
283
What is attached to the rod of the piston that allows it to do work?
Gears and levers
284
What do the gears in a steamboat turn to propel the boat forward?
A paddle wheel
285
True or False: Steamboats were primarily used for transporting goods and people in landlocked areas.
True
286
What does the piston do as the steam process repeats?
Moves back and forth
287
Fill in the blank: The steamboat was a common sight in what many people assumed was a _______.
landlocked prairie
288
Who first recorded a wheel turned by steam?
Hero of Alexandria
## Footnote
Hero described a toy-like device that utilized steam power.
289
What was the function of the pipe in Hero's steam wheel?
To carry steam from the pot to the hollow wheel
## Footnote
The steam caused the wheel to rotate due to pressure.
290
What happens to the water in the pot when placed over a fire?
It begins to boil
## Footnote
Boiling water produces steam, which powers the wheel.
291
How does steam power modern ocean liners?
Steam turns large turbines
## Footnote
Unlike paddle-wheeled boats, modern ships use turbines for propulsion.
292
What is a turbine?
A rotary engine used to convert fluid motion into mechanical energy
## Footnote
Turbines consist of fan blades attached to a central hub.
293
What does the steam do when it moves past the turbine blades?
Causes the blades to rotate
## Footnote
The rotation of the blades generates mechanical energy.
294
What is attached to the spinning turbine?
An axle that turns giant propellers
## Footnote
The propellers drive the ocean liner through the water.
295
Fill in the blank: A turbine consists of a number of _______ attached to a central hub.
fan blades
296
True or False: Paddle-wheeled riverboats are commonly seen today.
False
## Footnote
Paddle-wheeled riverboats have largely been replaced by modern vessels.
297
What role do stationary blades play in a turbine's efficiency?
They direct the angle at which steam hits the turbine wheel
## Footnote
This careful direction can improve the turbine's performance.
298
What are turbines used for?
Turbines are used in jet engines, to turn shafts that operate machines, and to provide electricity.
299
How do turbines generate electricity in thermo-electric generating stations?
In thermo-electric generating stations, burning coal is used to heat water to steam.
300
What alternative method is used to heat water in some turbines?
Nuclear reactors heat the water.
301
What is hydro-electric power generated from?
Hydro-electric power is generated by turbines powered by moving water.
302
True or False: Turbines are only used in ships.
False.
303
Fill in the blank: Turbines also provide _______.
electricity.
304
List three applications of turbines.
* Jet engines
* Operating machines
* Generating electricity
305
What is the significance of fluid pressure in ancient literature?
An early example of steam pressure used to operate a device
## Footnote
This showcases the historical use of fluid pressure before modern engines were developed.
306
When was the first useful steam engine developed?
The timeline includes the first useful steam engine's development
## Footnote
The specific date is not provided, but it marks a significant advancement in technology.
307
What were the improvements made in steam engines?
Improvements include:
* Use of steam turbines
* Increased efficiency and power output
## Footnote
Steam turbines allowed for greater efficiency in converting steam energy to mechanical work.
308
What is the first use of internal combustion engines?
The internal combustion engine was developed in Germany in 1876
## Footnote
This marked a major shift from steam-powered technology.
309
What is the process that occurs during the intake stroke of an internal combustion engine?
The piston moves down the cylinder and draws in the fuel-air mixture
## Footnote
This mixture is typically fine droplets of gasoline mixed with air.
310
What does 'internal combustion' refer to?
The combustion, or burning, of fuel occurs inside the engine
## Footnote
This is in contrast to external combustion engines that require a furnace and boiler.
311
How many pistons do internal combustion engines usually have?
Internal combustion engines usually have four, six, or eight pistons and cylinders
## Footnote
The number of pistons can affect the engine's power and efficiency.
312
What is the function of the crankshaft in an automobile engine?
The crankshaft changes up-and-down or back-and-forth motion to rotary motion
## Footnote
This rotary motion is essential for turning the automobile's wheels.
313
What happens during the power stroke of an internal combustion engine?
A spark ignites the fuel-air mixture, forcing the piston down
## Footnote
This process transfers energy from the piston to the wheels of the automobile.
314
What occurs during the compression stroke?
The piston moves up, compressing the fuel-air mixture
## Footnote
This compression increases the efficiency of the combustion process.
315
What is the purpose of the exhaust stroke?
The piston moves up again, compressing and pushing out waste products
## Footnote
This step is crucial for maintaining engine efficiency by clearing out exhaust gases.
316
What type of engine was ideal for early aircraft?
Internal combustion engine
## Footnote
Lighter and smaller compared to steam engines.
317
How long have internal combustion engines been in use?
More than 100 years
## Footnote
They continue to be tested and improved.
318
What was the maximum speed of the Silver Dart?
About 80 km/h
## Footnote
It was the first powered airplane flown in Canada.
319
What is the maximum speed of the Space Shuttle?
10 000 km/h
## Footnote
It can orbit at altitudes of 1 500 km.
320
What altitude could the Silver Dart reach?
Never flew above 100 m
## Footnote
It flew at an elevation of 3 to 9 m.
321
What was a key difference in travel technology between the Silver Dart and the Space Shuttle?
Travel time and distance
## Footnote
The Space Shuttle shortens travel time significantly.
322
What was the primary reason for early human travel?
Need for water supply
## Footnote
Whole villages would move if their water source dried up.
323
What role has science and technology played in travel?
Provided more and faster ways to travel
## Footnote
They have not changed the fundamental need to travel.
324
What is a significant feature of the Space Shuttle's design?
Consists of a winged orbiter and booster rockets
## Footnote
The boosters separate after using up their fuel.
325
How did the Silver Dart launch?
Pulled by a horse-drawn sleigh over ice
## Footnote
It was launched over Baddeck Bay in Cape Breton.
326
Fill in the blank: The Silver Dart flew at a speed of _______.
65 km/h
## Footnote
It flew for a distance of 0.8 km.
327
True or False: The Space Shuttle lands like an airplane.
True
## Footnote
After completing its mission, it reduces speed and descends.
328
What type of engine was ideal for early aircraft?
Internal combustion engine
## Footnote
Lighter and smaller compared to steam engines.
329
How long have internal combustion engines been in use?
More than 100 years
## Footnote
They continue to be tested and improved.
330
What was the maximum speed of the Silver Dart?
About 80 km/h
## Footnote
It was the first powered airplane flown in Canada.
331
What is the maximum speed of the Space Shuttle?
10 000 km/h
## Footnote
It can orbit at altitudes of 1 500 km.
332
What altitude could the Silver Dart reach?
Never flew above 100 m
## Footnote
It flew at an elevation of 3 to 9 m.
333
What was a key difference in travel technology between the Silver Dart and the Space Shuttle?
Travel time and distance
## Footnote
The Space Shuttle shortens travel time significantly.
334
What was the primary reason for early human travel?
Need for water supply
## Footnote
Whole villages would move if their water source dried up.
335
What role has science and technology played in travel?
Provided more and faster ways to travel
## Footnote
They have not changed the fundamental need to travel.
336
What is a significant feature of the Space Shuttle's design?
Consists of a winged orbiter and booster rockets
## Footnote
The boosters separate after using up their fuel.
337
How did the Silver Dart launch?
Pulled by a horse-drawn sleigh over ice
## Footnote
It was launched over Baddeck Bay in Cape Breton.
338
Fill in the blank: The Silver Dart flew at a speed of _______.
65 km/h
## Footnote
It flew for a distance of 0.8 km.
339
True or False: The Space Shuttle lands like an airplane.
True
## Footnote
After completing its mission, it reduces speed and descends.
340
What significant impact did the introduction of the first automobile have on society?
It allowed a large percentage of people to travel farther and faster.
341
What gasoline additive was discovered to cause pollution and health problems?
Lead tetraethyl.
342
What change has been made to gasoline in Canada to address pollution?
All vehicles use lead-free gasoline.
343
What is one of the negative consequences of automobile emissions?
Air pollution.
344
What was the common coolant used in refrigerators and car air conditioners that contributed to ozone layer destruction?
Freon 12.
345
What type of systems were developed as cities grew larger and more people moved to suburbs?
Mass-transit systems.
346
Fill in the blank: The development of machines throughout history has brought _______ and comfort to societies.
pleasure
347
What critical consideration must we make regarding the development of technology?
The problems and challenges that these technologies bring.
348
True or False: Freon 12 is still the most common coolant used in refrigerators today.
False.
349
What are we encouraged to learn from in order to make the future better?
Past experience.
350
List two types of choices we must make regarding advanced machines.
* Environmental impact
* Health implications
351
What is one way we are trying to meet the challenges posed by advanced machines?
Searching for alternative, less harmful technologies.
352
What invention transformed society during the Industrial Revolution?
The steam engine
## Footnote
The steam engine was invented by James Watt in 1769.
353
When did simple machinery begin to replace hand labor?
Since 1700
354
What was the capacity of the water-driven spinning machine introduced in 1769?
It could do the work of twelve workers.
355
Who developed a method of making iron using coal for fuel?
Henry Cort
356
What led to the rapid development of mass-production industry?
The iron to build machines and the engines to drive them.
357
Define mass production.
The manufacturing of large quantities of a standardized item by standardized mechanical processes.
358
Name three modern examples of mass production.
* Manufacture of home appliances in a factory
* Canning of foods in a food-processing plant
* Production of automobiles in an assembly plant
359
Which cities in England became industrialized due to the Industrial Revolution?
* Manchester
* Birmingham
360
What societal change occurred as a result of industrialization?
A transformation from a rural to an urban society.
361
What did spinners, weavers, and craftspeople do as factories emerged?
They flocked to the cities to find work.
362
True or False: The Industrial Revolution began after the introduction of the steam engine.
False
363
Fill in the blank: The steam engine was invented in _____ by James Watt.
1769
364
What was the impact of factories on rural families in the late 1700s?
They could not sell their cloth because it was made less expensively in factories.
365
What was a significant environmental change during the Industrial Revolution?
The urbanization of society.
366
What age groups worked long hours in factories during the Industrial Revolution?
Both children and adults.
367
What is the ongoing debate regarding technology and society?
Whether the needs or wants of society result in new technology or whether new technology changes society.
368
What is one argument for the large size of the oil industry?
The demand for fuel to run automobiles.
369
What is an alternative perspective on the prevalence of automobiles?
The low price and abundance of gasoline.
370
How do automobiles influence city structure?
They allow for the construction of large cities by making it easy to get around.
371
What significant change occurred in travel time for city commutes over the last century?
It used to take half a day to make a one-way trip, now it is much shorter.
372
What question does the text pose about the relationship between vehicles and city size?
Do cities exist because we have vehicles, or do we have vehicles because cities are large?
373
What was the public perception of fuel and pollution before the 1970s?
People thought fuel was unlimited and the atmosphere could absorb all pollutants.
374
What change occurred in public attitudes towards vehicles in the 1970s?
Attitudes changed due to awareness of fuel shortages and environmental effects of fuel combustion.
375
What are the older vehicle models in Figure 4.67 associated with?
A time when there was little concern for air pollution from vehicle exhaust.
376
What is the focus of comparison between the vehicles in Figures 4.67 and 4.68?
The obvious differences between older models and newer models.
377
What has happened to car motors and car design in the last thirty years?
Car motors have become smaller and cars more aerodynamic.
378
What inventions have become widely used in cars to improve efficiency?
Fuel injection and catalytic converters.
379
What is the benefit of the advancements in car technology?
Cars are more fuel-efficient and get better gas mileage.
380
What are the vehicles shown as alternatives to gasoline-powered vehicles?
Solar-powered racing car, electrically powered van, hydrogen fuel cell bus.
381
How does the racing car in Figure 4.69A generate energy?
It uses solar panels to capture the energy of the Sun.
382
How far can most electrically powered vehicles travel before needing a recharge?
About 80 km.
383
What fuels the bus in Figure 4.69C?
A hydrogen fuel cell.
384
What is the byproduct of the chemical reaction in a hydrogen fuel cell?
Water that is clean enough to drink.
385
True or False: The only exhaust from the hydrogen fuel cell bus is clean water.
True.
386
Who developed the hydrogen fuel cell mentioned in the text?
Ballard Power Systems.
387
Fill in the blank: The solar energy captured by the racing car is stored in a _______.
battery
388
What are some reasons why alternative fuel vehicles are not widely used?
Varied factors including cost, infrastructure, and consumer acceptance.
389
What is the process used by a hydrogen fuel cell to produce electricity?
A chemical reaction that uses hydrogen and oxygen.
390
What is the first step in designing a new technology or improving an existing one?
Start with a clear understanding of what you want the technology to do.
391
What were the two types of rail cars traditionally used?
Flat decks and boxcars.
392
How are modern rail cars designed?
Specifically designed for different tasks.
393
What must scientists and technicians do to ensure rail cars are performing as intended?
Constantly evaluate their work and ask questions.
394
What difficult questions do scientists sometimes have to ask themselves?
Should we proceed with a technology even if we have the understanding to design it?
395
What is a common concern regarding the use of nuclear power?
Accidents at nuclear power-generating plants can have devastating effects.
396
What are some considerations when purchasing a technological item?
* Energy required to make it
* Types of materials used
* Source of materials
* Waste generated
397
What should you evaluate regarding a mechanical device?
Whether its production and operation had any environmental or social costs.
398
True or False: All rail cars have the same design and use.
False.
399
Fill in the blank: Scientists must always ______ their work to ensure effectiveness.
evaluate
400
What is one benefit of nuclear power when functioning properly?
It is quite clean and causes little pollution.
401
What is one feature evaluated in the investigation regarding bicycles?
The comfort of each bicycle's seat
## Footnote
Comfort is a significant factor in the usability of bicycles.
402
What common experience is referenced to highlight seat discomfort?
Attending a sporting event or a concert
## Footnote
Many people can relate to discomfort in seating at large events.
403
What do cushions do to enhance comfort when watching sports events?
They make sitting easier
## Footnote
Cushions distribute weight and reduce pressure points.
404
How do inventors design more comfortable seats?
By using their understanding of scientific concepts related to force, area, and pressure
## Footnote
These concepts are fundamental in designing ergonomic products.
405
What is the difference in comfort between sleeping on the ground and sleeping on an air mattress?
An air mattress is more comfortable
## Footnote
An air mattress distributes weight better, reducing pressure on the body.
406
Fill in the blank: The relationship between ________, area, and pressure is crucial in designing comfortable seating.
force
## Footnote
Understanding the relationship helps in ergonomics and comfort design.
407
True or False: The comfort of a seat can affect the overall experience of watching an event.
True
## Footnote
Comfort plays a vital role in the enjoyment of events.
408
What is one feature evaluated in the investigation regarding bicycles?
The comfort of each bicycle's seat
## Footnote
Comfort is a significant factor in the usability of bicycles.
409
What common experience is referenced to highlight seat discomfort?
Attending a sporting event or a concert
## Footnote
Many people can relate to discomfort in seating at large events.
410
What do cushions do to enhance comfort when watching sports events?
They make sitting easier
## Footnote
Cushions distribute weight and reduce pressure points.
411
How do inventors design more comfortable seats?
By using their understanding of scientific concepts related to force, area, and pressure
## Footnote
These concepts are fundamental in designing ergonomic products.
412
What is the difference in comfort between sleeping on the ground and sleeping on an air mattress?
An air mattress is more comfortable
## Footnote
An air mattress distributes weight better, reducing pressure on the body.
413
Fill in the blank: The relationship between ________, area, and pressure is crucial in designing comfortable seating.
force
## Footnote
Understanding the relationship helps in ergonomics and comfort design.
414
True or False: The comfort of a seat can affect the overall experience of watching an event.
True
## Footnote
Comfort plays a vital role in the enjoyment of events.
415
What is the main focus of ergonomic research?
Increasing the comfort or efficiency of items
## Footnote
Ergonomics aims to optimize products for user comfort and performance.
416
How do technicians respond to findings from ergonomic research?
They quickly build, test, and market changes
## Footnote
This rapid response helps implement improvements based on scientific findings.
417
What types of items are tested for comfort and efficiency?
Safety belts and chairs
## Footnote
These items are assessed for their designed purpose and user comfort.
418
What has changed in wheelchair design over time?
Improvements in comfort and functionality
## Footnote
Advances allow users to participate in sports and daily activities.
419
What societal changes have influenced wheelchair technology?
Increased advocacy for the rights of people with disabilities
## Footnote
This advocacy has led to technological advancements and improved accessibility.
420
What are some examples of technologies that provide greater freedom for wheelchair users?
* Wheelchair ramps
* Specially designed washrooms
* Automatic doors
* Hand-operated vehicles and bicycles
## Footnote
These technologies enhance accessibility and independence for users.
421
What does the evolution of wheelchair design reflect?
Changes in society and advancements in science and technology
## Footnote
The design reflects societal attitudes and technological progress.
422
Fill in the blank: Ergonomic research has improved _______.
[wheelchair comfort]
## Footnote
This improvement is crucial for enhancing the user experience.
423
True or False: Ergonomics only focuses on comfort and does not consider efficiency.
False
## Footnote
Ergonomics aims to improve both comfort and efficiency.
424
What advancements have allowed wheelchair users to engage in sports?
Recent improvements in wheelchair design
## Footnote
Modern wheelchairs are designed for enhanced mobility and performance.
425
What historical items were not commonly known until recent times?
* Compact discs
* Personal computers
* Cellular phones
## Footnote
These innovations represent significant technological changes over time.
426
What role does testing play in ergonomic research?
Provides scientific information to researchers
## Footnote
Testing helps determine the best designs for comfort and safety.
