deck_2384172 (1) Flashcards
(157 cards)
1
Q
Does climbing stairs classify as doing work?
A
Yes, because you are going against the force of gravity.
2
Q
Does pushing a shopping cart qualify as doing work? (Assume there is friction.
A
Yes, you are applying a force against friction.
3
Q
What is the metric unit for work?
A
JouleA joule is also a unit for energy
4
Q
If you exert a force of 10N to lift a box 2m, how much work did you do?
A
20 J(10N)(2m)=20J
5
Q
What is the SI unit for power.
A
Watt
6
Q
If you exert a force of 5N to travel 10m in 2s how much power was used?
A
25W(5N)(10m)/2s=25
7
Q
1492 watts ls about how many horsepower?
A
2
8
Q
What can a machine multiply? (Two answers can apply)
A
Force, Distance
9
Q
How does a machine make it so that you can apply less force?
A
The machine allows you to apply the force over a greater distance.Changes the direction of the force.No matter what the total energy required to do the work must remain the same.
10
Q
Can a machine reach100% efficiency?
A
No, because some of the work input is always lost to friction.
11
Q
How do you figure out the ideal mechanical advantage of a pulley system?
A
Count the number of rope segments that supports the weight.
12
Q
A machine that is made up of one or more simple machines.
A
Compound Machine
13
Q
What is transferred by a force moving an object through a distance?
A
Energy
14
Q
The energy of motion.
A
Kinetic Energy
15
Q
Ignoring wind resistance and friction, would doubling the height of a roller coaster double its speed? Explain why or why not.
A
No. The speed would be less than double because V^2=2ad.
16
Q
What sort of energy would each of the following have?A wound up wind up toy, A stretched rubber band, An inflated tire.
A
Elastic Potntial
17
Q
I drop a ball that weighs 2 kg from a 3 m height. What is the balls gravitational potential energy?
A
About 60 JEP=(2kg)(3m)(9.8m/s^2)
18
Q
What type of energy increases when an object gets warmer?
A
Thermal Energy
19
Q
The energy that is stored in coal is what type of energy?
A
Chemical
20
Q
This type of energy is defined as the total potential and kinetic energy of all the microscopic particles in an object.
A
Thermal Energy
21
Q
What type of energy supplies your body with energy?
A
Chemical energy that is stored in the food that you eat.
22
Q
The Sun uses what sort of energy?
A
Nuclear EnergySimilar, but opposite to the source of power for nuclear power plants.
23
Q
What energy conversion happens in the Sun?
A
Nuclear into LightSolar cell convert light energy into electricity.
24
Q
Explain what E=mc^2 means in words.
A
Energy equals mass times the speed of light squared.This shows that energy can be converted into mass and vice versa.
25
Why are fossil fuels the primary source of energy for the world?
Because they are relatively inexpensive and readily available.Although as easy to reach sources are used up this quality is changing.
26
How is temperature measured in the metric system?
Celsius Degrees, KelvinCelsius is based on the melting and boiling of water.Kelvin is based on absolute zero.
27
Thermal energy transfers from one substance to another because of differences in...
Temperature
28
The measure of the average kinetic energy in an object, is the objects?
Temperature
29
What three things does an object thermal energy depend on.
Its mass phase and temperature.
30
What is the difference between conduction, convection and radiation.
Conduction, convection, and radiation are all forms of heat transfer. The differences are in how the heat transfers. Conduction is through direct contact, convection is through fluid movement, and radiation is through electromagnetic waves.
31
Is metal a good conductor or a bad conductor? Explain why.
Metal is a good conductor because it transfers heat and electricity well.
32
What is the name of the fluid that is found in air conditioners?
Refrigerant
33
What heating system involves heating water, and pumping it throughout a house?
Radiant HeatingAs opposed to forced-air that involves a furnace and a blower.
34
A steam engine is an example of what kind of engine?
External combustion Chemical energy is released outside of the engine which heats water into steam converting heat into work.
35
What does the first law of thermodynamics state?
That energy cannot be created or destroyed it only changes form.
36
What does the second law of thermodynamics state?
Thermal energy can flow from colder objects to hotter objects only if work is done on the system.
37
What does the third law of thermodynamics state?
Absolute zero can never be reached.Absolute zero is where the subatomic particles cannot slow down any more.
38
What is the SI unit for force?
Newton
39
What is the total force on a tug of war rope if one team is pulling with 5N of force and the other team is pulling in the opposite direction with 5N of force?
10N of force.
40
What is the net force on a tug of war rope if one team is pulling with 5N of force and the other team is pulling in the opposite direction with 5N of force?
0N of force.The forces are balanced.
41
What are two of the major forces that determine the speed of a parachutist?
The downward force of gravity, and the upward force of wind resistance.
42
What two things make thrown objects follow a curved path.
The initial forward velocity of the abject, and the force of gravity.
43
Why would a car slide of the road in the wintertime?
If the forward inertia of the car is greater than the friction between the tires and the road, the car will slide of the road.
44
What does Newton's second law of motion state?
Force equals mass time acceleration.
45
What is the difference between weight and mass?
Mass is the measure of the amount of substance in an object. Weight is the measure of the force of gravity on a mass.Weight equals mass times the force of gravity.
46
What does Newton's third law of motion state?
For every action there is an equal and opposite reaction.
47
What is the momentum of a 2kg toy car that is travelling at 3m/s?
6kgm/sm=m*v=2kg*3m/s.
48
What can a wave transfer?
Energy
49
What part of a wave directly relates to the pitch of a sound?
The wavelength or frequency
50
What happens to the frequency of a wave as the wavelength goes up?
The frequency goes down.
51
What happens to the volume of a sound as distance increases?
The volume goes down.
52
How do sound waves spread as they move away from a sound source?
They spread out in all directions.
53
What part of a wave directly relates to the volume of a sound?
The amplitude
54
What type of a wave is a sound wave?
Mechanical and compressional
55
What are the two types of mechanical waves?
Compressional/ longitudinal, Transverse
56
Name the types of medium can a mechanical wave transfer through?
Solids, liquids, gasses
57
What can a mechanical wave not pass through?
A vacuum
58
Explain how refraction works?
When waves travel from one medium to another they change direction.
59
What can be said about the speed of sound in the air at sea level?
It remains constantAt about 343 m/s depending on the temperature.
60
What happens to the speed of sound in different types of medium?
It changes
61
What are four things that can be measured in a wave?
Speed, frequency, wavelength, amplitude
62
What are two types of waves?
Electromagnetic, mechanical
63
What are the similarities between transverse and longitudinal waves?
They both transfer energy.They do not transfer particles.
64
Explain how you would measure frequency?
Pick a particular time period and count how many waves pass by over a certain time.
65
What are the differences between transverse and longitudinal waves?
Transverse waves move up and down. Perpendicular to the movement of energy.Longitudinal waves move back and forth, parallel to the movement of energy.
66
What is a period?
A certain length of time. For waves the period is the amount of time a frequency is based on.
67
How would you measure amplitude?
Determine the distance between the rest position to either a crest or a trough.
68
What are two ways that waves carry energy?
In higher amplitudes, and in higher frequency.
69
What happens when a wave "bounces" off of a solid object?
Reflection
70
What happens when a wave changes direction because it has went from one medium to another?
Refraction
71
What happens when a wave passes through multiple openings and interferes with itself?
Diffraction
72
What happens when two waves occupy the same space?
The waves could build on each other (constructive interference) if the peaks and troughs line up.The waves could have destructive interference if the peaks and troughs are opposite of each other. Or anything in-between.
73
How does sonar work?
A tone is sent out. It bounces off something and is received again. If you know the speed of sound you can calculate the distance.
74
Describe the Doppler effect.
Objects moving toward you will make sounds in a higher pitch. Objects moving away will have a lower pitch.
75
What is the definition of one hertz?
A hertz is a wave per second.i.e. 5 hertz is five waves in a second.
76
What is the name for a wave that travels at the top of a given medium?
Surface Wave.
77
What kind of lines does a + sign have?What about an = sign?
+ perpendicular= Parallel
78
What is the definition of a period as it directly relates to waves?
A period is the time it takes for one wave to pass.If you have a 2hz wave its period is a half a second.
79
How does a standing wave form?
When an ingoing and outgoing wave interfere with one another.
80
What three properties of a wave are different between red light and blue light.
Wavelength, Frequency, EnergyAll electromagnetic waves have the same speed, and reflecting properties.
81
How was the speed of light determined? What is one of the issues of measuring the speed of light?
The big issue with measuring the speed of light is that it moves so fast. Because of this mirrors were used to increase the distance that the light had to travel making it easier to measure.
82
What two things do you need to know about a wave in order to calculate its frequency?
The waves speed, and its wavelength.
83
Isaac Newton hypothesized that light was a stream of particles because...
It travels in a straight line and casts a shadow.Unrelated to the test light can also travel through a vacuum.
84
What two things does an electromagnetic wave behave like?
A wave and a particle.
85
Why does light get dimmer as it moves away from its source?
The photons are spread out over a larger area.
86
How do photons travel from a light source?
In all directions.Although once released light travels in a straight line.
87
Infrared rays are between what two other parts of the electromagnetic spectrum?
Microwaves and visible light. (The test mentions radar)
88
The waves with the longest frequencies in the electromagnetic spectrum are the...
Radio waves
89
The full range of frequencies of electromagnetic waves is the ...
Electromagnetic spectrum
90
X-ray photographs show softer tissue as...
Dark highly exposed areas.This is because the x-rays pass through the softer material and are blocked by the dense material.
91
Visible light lies between what two areas of the electromagnetic spectrum?
micro waves and ultraviolet waves
92
What does a translucent material do...
Scatters some, but not all of the light.
93
Order the light transmitting properties of materials from all light to no light.Opaque, Translucent, Transparent
Transparent, Translucent, Opaque
94
What is the term for when light changes direction when it passes from one medium to another?
Refraction
95
How do polarized sunglasses work?
It blocks the light that vibrates in certain planes.
96
What did Newton's prism experiment discover?
That visible light was made up of all the colors.
97
What is the name of the process hat creates a rainbow from raindrops?
DispersionThe raindrops act as a prism.
98
What determines the color of an object?
What it is made of and the color of light that hits it.
99
Blue light and yellow light combine to form white light because they are...
Complimentary colors of light.
100
The primary colors of light are...
Red, Blue, Green
101
An incandescent bulb produces light when the electrons flow through the...
FilamentThe filament is usually a metal that heats up when the electrons flow through.
102
Why do neon lights glow red.
The red color comes from the electron configuration of Neon.The color of the glass tubing does not make the light red.
103
Light whose waves all have the same wavelength frequency and coincidental peaks is...
CoherentLasers produce coherent light.
104
What gas is inside a fluorescent light?
Mercury
105
How does the angle of incidence compare to the angle of reflection in a plane mirror?
They are equal.
106
How is the iris of the eye similar to the diaphragm of a camera?
They both control the amount of light that passes through.
107
The human eye focuses light by...
Changing shape.
108
How does a microscope produce an image for you to see?
The objective lens produces an image that becomes the object for the eyepiece lens.
109
A compound microscope uses...
2 small convex lenses to magnify a small object.
110
Which part of a film camera focuses the incoming light rays.
Lens
111
What must be done in a film camera to focus the image?
The lens must be moved toward or away from the film.
112
What sort of image is produced by a refracting telescope? What size? Is it real?
Enlarged virtual
113
A light ray passes through a glass of water to the other side. How many times does it refract?
4 air-glass, glass-water, water-glass, glass-air
114
Light refracts when it... 3 answers
Changes mediumChanges speedChanges direction
115
Why do plane mirrors and convex mirrors only form virtual images?
The reflected rays appear to come from behind the mirror.
116
What type of images can a concave mirror form?
Virtual and real images
117
The point at which reflected rays intersect is the...
Focal point
118
What is the major difference between a real image and a virtual image?
A real image can be viewed on a screen.
119
Where do the light rays appear to be coming from in a plane mirror?
Behind the mirror.
120
What is a mirror with a flat surface called?
Plane mirror
121
What is the angle of incidence?
The angle that an incident ray makes with a mirror.
122
What three things affect a materials resistance?
Thickness, Length, Temperature, (Composition)Resistance is a materials ability to conduct electrons
123
What does increasing the diameter of a wire do to its resistance?
It would reduce the resistance.Gauge is the measure for wire thickness. The lower the gauge the thicker the wire. Low gauge wire has less resistance.
124
If the current of a device is 2 amps and its resistance is 10 ohms what is the voltage of the iron?
20v(2 amps)(10 ohms)=20v
125
Electrical signals sent by smoothly and continuously changing the voltage or current in a circuit are?
Analog SignalsAs opposed to digital signals that rapidly change between two set positions.
126
What two things determine the strength of an electric field?
The distance from the charge.The amount of the charge that produced the field.
127
What is the unit for electrical power?
Watt
128
A material that has electrons that are tightly bound to its atoms is generally an...?
InsulatorTightly bound electrons do not flow easily.
129
A power cord is made up of a copper wire surrounded by a rubber coating. Explain why these two material were chosen to make a power cord.
The copper is a conductor which allows electrons to flow through.The rubber is an insulator which keeps electrons from flowing outside of the wire.
130
What is the purpose of a circuit breaker?
To open a circuit when the wattage flowing through the circuit gets too high. This prevents damaging devices that are plugged in to the circuit.
131
What is the purpose of a ground fault circuit interrupter? (GFCI outlet)
It shuts off a circuit in case of a short circuit.GFCI outlets should be used anyplace where water may get into an outlet.
132
The type of current that is supplied through wall outlets in the U.S. is...?
Alternating current. The direction of the current cycles 60 times per second (hz) in the U.S. Ever wonder why the plugs are different in Europe?
133
How many paths can electricity follow in a series circuit?
One
134
What is maintained across the terminals of a battery? (2 answers)
A voltage dropA potential difference
135
What type of current is produced by a battery?
Direct Current
136
What information do you need to know to calculate the power consumption of an appliance? What do you do with this information?
You need to know the amps and the voltage.Multiply the amps times the volts.The test question is similar but different.
137
If a neutral metal comb is held near an object with a negative charge it will become charged by...
InductionThe electrons move from high concentration to low concentration.
138
What happens when two objects of opposite charge are brought near each other.
They attract.They will also exchange charges to become more neutral.
139
Information that is sent in codes and patterns that are embedded in a controlled flow of electrons are...
electronic signalsElectronic signals can be in analog or digital format.
140
What charge does an object take on when it gains electrons?
Negative
141
The difference in electrical potential energy between two places in an electric field is called the...
Potential difference
142
Walking across a carpet is an example of charge being transferred by...
Contact
143
What is the name of the force that magnets exert on other magnets, iron or similar metal, or moving charges?
Magnetic Force
144
Explain how the poles of a magnet interact with each other.
Like poles repel.Opposite poles attract.Just like protons and electrons.
145
How does the magnetic force between objects change as the distance between the two objects is decreased.
The magnetic force increases.Many other forces act the same way as the same amount of forceis spread out over a larger area.
146
What is the name of the area surrounding Earth that is influenced by the Earth's magnetic field?
Magnetosphere
147
What is the name for a ferromagnetic material hat has domains that are aligned for a long period of time?
Permanent MagnetAs opposed to temporary magnets that constantly need to be remagnetized.
148
How can a permanent magnet be demagnetized?
Heat the magnet up.Strike the magnet with a heavy blow.
149
What creates a magnetic field?
Moving electric charges.
150
Why is a soft iron usually used in the cores of electromagnets?
The are easily magnetized.Electromagnets are commonly used in situations where the magnetic field needs to be "turned" on and off.
151
In an electric motor, periodically changing the direction in the electromagnet can cause the axle to spin because...
The magnetic field reverses direction.
152
The process of generating an electric current by moving an electrical conductor relative to a magnetic field is called?
Electromagnetic induction
153
What is the name of a device that converts mechanical energy into electricity?
Generator
154
How are fossil fuels used to generate electricity? (3 major steps)
Heat from burning fuel creates steam that spins a turbine (which is connected to a generator that makes electricity). The generator spins 60 time per second, making our AC current.
155
What is a solenoid?
A coil of wire that is carrying a current and producing a magnetic field.
156
Where is the magnetic force greatest on a bar magnet?
Toward the poles.
157
What determines the strength of the output voltage of a transformer?
The number of turns in the primary and secondary coils.
