Exam 2 Flashcards
(137 cards)
0
Q
What type of models allow u to think about how to complete the solution?
A
Mental models
1
Q
What kind of models show how variables relate to each other?
A
Scientific models
2
Q
Why kind of models help take the guess work out by providing hands on?
A
Physical models
3
Q
What refers to proportion?
Ex: 1inch=1foot
A
Scale
4
Q
What type of model is descriptive in nature and shows how something works?
A
Conceptual model
5
Q
Who described a heliocentric model?
A
Copernicus
6
Q
Who invented a telescope and documented movement of stars?
A
Galileo
7
Q
Who took data from Brahe and derived planetary motion laws?
A
Kepler
8
Q
Who used info from previous men and derived the law of universal gravitation?
A
Newton
9
Q
What kind of model has a dependent variable and an independent variable?
A
Graphical models
10
Q
Which variable goes on the y axis?
A
Dependent variable
11
Q
Which variable goes on the x axis?
A
Independent variable
12
Q
Where an object is located in some respect to some other object
A
Position (displacement)
13
Q
Direction when graphing
A
North: top of paper
East: right of paper
South: bottom of paper
West: left of paper
14
Q
The measurement of the path you took
A
Distance
15
Q
The measurement from point A to point B
A
Displacement
16
Q
Something that includes 2 properties
A
Vector quantity
17
Q
Vector quantities of displacement
A
Direction and magnitude
18
Q
Measure of length, and strength
A
Magnitude
19
Q
North, south, east, west, up/down, positive/negative
A
Direction
20
Q
Slope of the position vs time graph
A
Speed
21
Q
Ratio of rise/run
A
Slope
22
Q
The rate at which speed changes or a changing of direction of an object
A
Acceleration
23
Q
Speeding up (positive)
A
Acceleration
24
Slowing down (negative)
Deceleration
25
Acceleration formula
A=Vf-Vi/Tf-Ti
Or
Change in velocity over change in time
26
Units for acceleration
m/s/s
Or
m/s^2
27
No acceleration occurs if....
Velocity is constant
28
Accelerates objects towards earth
Gravity
29
Rate of gravity
9.8m/s/s
30
Slope on a velocity-time graph
Acceleration
31
What force opposes motion of the object?
Friction
32
What causes the wearing away of surfaces?
Friction
33
Types of friction
Static
Sliding
Rolling
34
What type of friction occurs when the surfaces don't move? (The most friction is produced)
Static
35
What type of friction occurs when the two surfaces move? (Medium friction occurs)
Sliding
36
What friction occurs when a round object moves over a surface? (Least friction produced)
Rolling friction
37
The mass of an object times the velocity of the object
Momentum
38
What is momentum measured in?
Kg•m/s
39
Momentum formula
P=mv
40
The tendency of an object to resist change in motion
Inertia
41
The total momentum of a system remains constant if all outside forces acting on the system are total zero
Law of conservation of momentum
42
A device with moving parts that work together to accomplish a task
Machine
43
What you do to make the machine function
Input
44
What the machine does for you, making work easier, not less
Output
45
List the six types of simple machines
```
Lever
Pulley
Wheel and axel
Wedge
Screw
Inclined plane
```
46
An unpowered mechanical device
Simple machine
47
The ratio of output force to input force
Mechanical advantage
48
Formula for MA
MA=Fo/Fi
| MA=output force/input force
49
Pulling force which acts along the direction of the rope
Tension force
50
In a block and tackle system, MA is dependent on the number of ______.
Supporting ropes
51
A stiff material such as a board, crowbar, etc. that is supported and pivots around a fixed point called the fulcrum
Lever
52
The arm in a lever where force is applied
Input arm
53
Arm in a lever where the load to be moved is located
Output arm
54
Class of lever with fulcrum in the middle
1st
55
Class of lever with output in the middle
2nd
56
Class of lever with input in the middle
3rd
57
The application of science to solve problems
Engineering or technology
58
Part of engineering cycle where research is done
Conceptual design
59
Part of engineering cycle where you build models
Prototype
60
Part of engineering cycle where the model is given the chance to succeed or fail
Test
61
Part of engineering cycle where you identify the good and bad points of the prototype
Evaluation
62
VOE
Car designer
63
Why are gears better than wheels?
Teeth dont slip
64
Formula for gears
Output turns/input turns = input teeth/output teeth
65
Force times the distance moved in the direction of the force
Work
66
Work formula
W=f•d
| Work = force • distance
67
What things prevent machines from getting 100% efficiency?
Friction, thermodynamics, and other work losses
68
Efficiency formula
Eff. = Wo/Wi • 100% = _______%
69
Rate at which work is done
Power
70
Formula for power
P=w/t
| Power = work/time
71
Unit for power
Watts
72
Unit for work
Joules
73
Who was the watt named after?
James watts, inventor of the steam engine
74
746 Watts or 550 ft•lb/sec =
1 horsepower (hp)
75
Ability to do work
Energy
76
Unit for energy
Joules
77
Energy based on position or situation
Potential energy (Ep)
78
Formula for potential energy
Ep=mass•gravity•meters
79
Unit of potential energy
Kg•m^2/s^2
80
Energy of motion
Kinetic energy (Ek)
81
What 2 things does kinetic energy depend on?
Mass and speed
82
Formula for kinetic energy
Ek = 1/2mv^2
83
Formula for energy conservation
Epi+Eki=Epf+Ekf
| Initial potential energy+Initial kinetic energy = Final potential energy+Final kinetic energy
84
List other types of energy
Radiant
Electrical
Chemical
Nuclear
85
The flow of electric current through wired or devices
Electricity
86
Paths by which electricity flows or follows
Electric circuits
87
Used to break or complete a circuit
Switches
88
Gives a basic idea of the parts of a circuit and the path of flow
Circuit diagram
89
Electrical symbol for wire
________
90
Electrical symbol for battery
-----| i-----
91
Electrical symbol for light bulb
___Q___
92
Any device which uses energy
Resistor
93
An incomplete circuit
Open circuit
94
A complete circuit
Closed circuit
95
A circuit with an alternate path
Short circuit
96
Who discovered the principle of the electric motor
Michael Faraday
97
A fundamental property of matter
Electric charge
98
Build up of electricity
Static charge
99
Like charges ______
Repel
100
Opposite charges ______
Attract
101
What do we measure electric charge in?
Coulombs
102
Who was first to succeed in making accurate measure of lightning
Charles Augustin de Coulomb
103
Positive charge
Protons
104
Negative charge
Electrons
105
Coulomb constant
8.99•10^9 Nm^2/c^2
106
A simple device which detects electric charge
Electroscope
107
Defined as the potential difference between 2 points
Voltage
108
Uses chemical energy to move charges
Battery
109
Motors which spin and create voltage
Generators and alternators
110
The amount of voltage difference between the positive end and the negative end = total watts
In a battery
111
Current flows from _____ voltage to ______ voltage
Higher to lower
112
Allows charges to flow easily and without much loss of energy
Conductors
113
Who invented the battery in 1800?
Alessanzo Volta
114
Defined as the flow of electric charges
Current
115
Current is measured in _____
Amperes
116
Electrical fires occur when...?
Too much current moves through a circuit
117
What devices help prevent electrical fires?
Circuit breakers, fuses, and GFCI
118
D.C.
Direct current
119
A.C.
Alternating current
120
Flows in one direction- from positive to negative, but the e- move from negative to positive
Direct current
121
The flow of the current oscillates or moves back and forth
Alternating current
122
How easily charges flow through a material
Resistance
123
Move charges more easily
Conductors
124
They can move charges due to their chemical makeup
Semiconductors
125
Do not allow charges to flow
Insulators
126
The property of a material to allow charges to flow
Electrical conductivity
127
The lowest voltage at which an insulator turns into a conductor
Breakdown voltage
128
Ohms
Unit of resistance
129
Resistance formula
R=V/I
130
This occurs when charges bounce into atoms
Resistance
131
A device which maintains temperature and current over a wide range
Resistor
132
Maintains the same value
Fixed
133
Not consistent or adjustable
Variable
134
A variable resistor
Potentiometer
135
An electrical path which current has only one way to go
Series circuit
136
An electrical path which current has more than one path
Parallel circuit
