Physics Definitions and Equations Flashcards Preview

AP Exam Review > Physics Definitions and Equations > Flashcards

Flashcards in Physics Definitions and Equations Deck (93):
1

Acceleration

How much an object's speed changes in one second

2

Kinematics Equations (4)

Vf = Vo+at
x = Vot+1/2at^2
Vf^2 = Vo^2+2ax
x = 1/2t(Vo+Vf)

3

Angular Momentum (Extended object) Equation

L = Iw

4

Angular Momentum (Point object) Equation

L = mrv

5

Impulse- Momentum Theorem Equation

torque(time)= L
(Change in angular momentum equals the net torque multiplied by the time the torque is applied)

6

Displacement

How far an object ends up from its initial position

7

Average Velocity

Displacement divided by the time interval over which that displacement occurred

8

Instantaneous Velocity

How fast an object is moving at a specific moment in time

9

How to determine how far from the detector an object is located (Position-time graph)?

Look at the vertical axis of the position-time graph

10

How to determine how fast an object is moving (Position-time graph)?

Look at the steepness/slope of the position-time graph

11

How to determine which way the object is moving (Position-time graph)?

Look at which way the position-time graph is sloped

12

How to determine how fast an object is moving (Velocity-time graph)?

Look at the vertical axis of the velocity-time graph

13

How to determine which way the object is moving (Velocity-time graph)?

Look at whether the velocity-time graph is above or below the horizontal axis

14

How to determine how far an object travels (Velocity-time graph)?

Determine the area between the velocity-time graph and the horizontal axis

15

When an object is in free-fall...

Vertical acceleration is always 10 m/s
Horizontal acceleration is always zero

16

Angular Displacement (Theta)

The angle through which an object has rotated (radians)

17

Average Angular Velocity (w)

Angular displacement divided by the time interval over which that angular displacement occurred (rad/s)

18

Instantaneous Angular Velocity

How fast an object is rotating at a specific moment in time

19

Angular Acceleration (fishy a)

How much an object's angular speed changes in one second (rad/s^2)

20

Difference between angular acceleration and centripetal acceleration?

Angular acceleration changes an object's rotational speed.
Centripetal acceleration changes an object's direction of motion.

21

Linear Displacement (Rotating object) Equation

x = r(theta)

22

Linear Speed (Rotating object) Equation

v = rw

23

Linear Acceleration (Rotating object) Equation

a = r(fishy a)

24

Torque Equation

torque = Fd

25

Rotational Inertia (I)

Resistance to angular acceleration

26

Rotational Inertia (Point particle) Equation

I = MR^2

27

Angular Acceleration Equation

fishy a = net torque / I

28

Mechanical energy is conserved when?

No net work done by external forces

29

Angular momentum is conserved when?

No net external torque acts

30

Momentum in a direction is conserved when?

No net external force acts in that direction

31

Momentum Equation

p = mv
(mass times velocity)
Units: Newton seconds

32

Impulse Equation

J = change in momentum
J = Ft
Units: Newton seconds

33

What is impulse in a force-time graph?

The area

34

Crest

High points on a wave

35

Trough

Low points on a wave

36

Amplitude (A)

The distance from the midpoint to the crest or trough

37

Wavelength (lambda)

The distance between identical parts of the wave

38

Frequency (f)

The number of waves to pass a position in one second
Units: Hertz (Hz)

39

Period (T)

The time for one wavelength to pass a position

40

Frequency Equation

f = 1/T

41

Period Equation

T = 1/f

42

Speed of a Wave Equations (2)

v = lambda(f)
v = lambda/T

43

Transverse Wave

Motion of a material is at right angles to the direction in which the wave travels

44

Longitudinal Waves

A material vibrates parallel to the direction of the wave

45

Interference

Waves arrive at the same point at the same time

46

Constructive Interference

Crest of one wave overlaps the crest of another.
Result: Wave of increased amplitude

47

Destructive Interference

Crest of one wave overlaps the trough of another
Result: Wave of reduced amplitude

48

Superposition

Where the wave pulses overlap, the resulting displacement can be determined by adding the displacements of the two pulses

49

Beats

When two waves of slightly different frequency interfere. Beat frequency is the difference between the frequencies of the two waves

50

Doppler Effect

Change in frequency due to motion of the source.
Wave source approaches...waves with higher frequency
Wave source moves away...waves with a lower frequency

51

What does the pitch of a sound depend on?

Sound wave's frequency

52

What does the loudness of a sound depend on?

Sound wave's amplitude

53

What does the energy carried by a sound wave depend on?

Wave's amplitude

54

Standing Wave

Wave that appears to stay in one place

55

Nodes

Stationary points on a standing wave

56

Antinodes

Positions on a standing waves with the largest amplitudes

57

Fundamental

The lowest frequency standing wave

58

How is wavelength measured on a standing wave?

Node to node

59

What is the fundamental frequency for a standing wave with identical boundaries?

v/2L
Harmonies exist in all multiples of the fundamental

60

What is the fundamental frequency for a standing wave with different boundaries?

v/4L
Harmonies exist only in odd multiples of the fundamental

61

Object in Equilibrium

The object moves in a straight line at constant speed. The net force is zero.

62

Force

Push or pull that acts on an object. It is always in the direction of acceleration.

63

Force Equation

F = ma
Units: Newtons

64

Equilibrium Force Equations

(up force)-(down force) = 0
(left force)-(right force) = 0

65

Mass

Tells how much material is contained in an object

66

Weight

Force of a planet acting on an object

67

Normal force

Force of a surface on an object in contact with that surface. It acts perpendicular to the surface.

68

What is the resultant force when two concurrent forces act perpendicular to one another?

Greater than if the forces acted in opposite directions, but less than if the forces acted in the same direction.

69

What is the horizontal and vertical component of a force when the angle of the diagonal force is measured from the horizontal?

Horizontal component is the magnitude of the force times cos(theta)
Vertical component is the magnitude of the force times sin(theta)

70

Force of Friction

Force of a surface on an object acting along the surface

71

Force of Friction Equation

Ff = uFn
(Force of friction equals the coefficient of friction times the normal force)

72

Difference between kinetic friction and static friction?

Kinetic friction is used when an object is moving. Static friction is used when an object is not moving.

Maximum coefficient of static friction is greater than the coefficient of kinetic friction.

73

Newton's LUG

All massive objects attract each other with a gravitational force

74

Gravitational force (Fg) Equation

Fg = G (M1M2)/d^2

75

Gravitational Field (g) Equation

g = GM/d^2

76

Weight (aka gravitational mass) Equation

weight = mg
(gravitational mass is equal to inertial mass)

77

Inertial Mass Equation

F = ma
(inertial mass is equal to gravitational mass)

78

Component of the Object's Weight (Parallel to incline) Equation

mg(sin(theta))

79

Component of the Object's Weight (Perpendicular to incline) Equation

mg(cos(theta))

80

Newton's Third Law

Force of object A on object B is equal to the force of object B on object A

81

Circular Motion Acceleration Equation

v^2/r directed towards the center of the circle

82

Work Equation

W = Fx
(force multiplied by the distance an object moves parallel to that force)

83

What is work in a force-displacement graph?

The area

84

What are the units for energy?

Joules (J)

85

Kinetic Energy Equation

KE = 1/2mv^2

86

gravitational Potential Energy Equation

PE = mgh

87

Mechanical Energy Equation

KE+PE = ME

88

Spring Potential Energy Equation

PE (spring) = 1/2kx^2

89

Rotational Kinetic Energy

KE (rotational) = 1/2Iw^2

90

Work- Energy Theorem Equation

W (external) = (KEf-KEi) + (PEf-PEi)

91

Force of a Spring Equation

F = kx
Units: Newton/meters

92

Power Equation

p = work/time
p = Force(velocity)
(amount of work done in one second)

93

What has the largest rotational inertia?

Hoop (I = mR^2)
(Other rotational inertia equations contain a fraction before it)