Physics 1: Kinematics, Energy, Momentum, Work

Question 1

Forces are vectors required to change _____ and can be caused by any push or pull.

Answer 1

velocity

Question 2

Examples of push/pull forces used to change velocity

Answer 2

Gravity
Friction
Rotation

Question 3

_____, like Forces, are vectors that can cause a change in velocity. Net ____ must be equal to 0 to maintain equilibrium.

Answer 3

Torques

Question 4

Forces that act over a distance

Represents a change in energy

Answer 4

work

Question 5

May be converted from kinetic to potential and back but total value must always be conserved

Answer 5

energy

Question 6

even if some energy is lost to the environment, _____ is always conserved in collisions

Answer 6

momentum

Question 7

VAT Kinematic Equation

Answer 7

Vf = Vo + a*t

Question 8

VAX Kinematic Equation

Answer 8

Vf^2 = Vo^2 + 2ax

Question 9

VTAX Kinematic Equation

Answer 9

x = Vo * t + 1/2 * a * t^2

Question 10

Uniform Acceleration Equation

Answer 10

x = 1/2 (Vo + Vf) * t

Question 11

Equation: When PE completely converted to KE

Answer 11

V^2 = 2gh

Question 12

Definition: Newton’s First Law

Answer 12

Inertia

an object in motion (or at rest) will stay in motion (or at rest) unless acted on by a net outside force

Question 13

Definition: Newton’s Second Law

Answer 13

To change velocity, you need a Force, which produced acceleration

Question 14

When does acceleration = 0?

Answer 14

when an object is not moving

when velocity is constant

Question 15

SI Unit: Force

Answer 15

Newtons = kg*m/sec^2

Question 16

A falling object accelerating due to gravity will encounter air resistance _________ to its increasing velocity

Answer 16

proportional

Question 17

At terminal velocity, the air resistance equals _______, resulting in no Fnet and no acceleration

Answer 17

force of gravity

Question 18

Definition: Newton’s Third Law

Answer 18

Every action has an equal and opposite reaction

Force pairs must be the same TYPE of force (i.e. Gravity, Normal Force)

Question 19

Newton’s Third Law only applies to gravity when?

Answer 19

If you enlarge the system to include to include the source of gravity, i.e. the Earth itself

Question 20

The force exerted by a surface that opposes

acts perpendicular to the surface

Answer 20

Normal Force

Question 21

If F(net) = 0, and the only other force acting on the object is gravity, then the magnitude of the normal force (Fn) = ?

Answer 21

F(g) = m*g

*Note: g = accel due to gravity= ~10 m/s^2

Question 22

If an elevator is accelerating upward, F(n) also includes opposition to the force of upward acceleration (m*a), so F(n) = ?

Answer 22

F(n) = ma + mg

Question 23

If an elevator is accelerating downward, F(n) = ?

Answer 23

F(n) = ma - mg

Question 24

A weight scale measures ______

Answer 24

the normal force

Question 25

tendency of objects to stick together, opposing new forces | opposes movement

Answer 25

Friction

Question 26

type of friction between two objects that are sitting still varies w/ the force applied has an absolute maximum, after which motion occurs and this value drops to zero

Answer 26

static friction

Question 27

type of friction between moving objects | proportional ONLY to the Normal force, not the force applied

Answer 27

kinetic friction

Question 28

tendency of masses to attract other masses | force is always attractive

Answer 28

gravity

Question 29

Equation: Force due to gravity

Answer 29

F(g) = G *m1 * M2 / r^2 = m*g Note: G-gravitational constant; g = accel due to g; M-mass of earth; m-mass of object; r-radius of Earth from center to surface

Question 30

sin(0)

Answer 30

= 0 (square root 0/2)

Question 31

sin(30)

Answer 31

= 1/2 (square root of 1/2)

Question 32

sin(45)

Answer 32

= square root of 2/2

Question 33

sin(60)

Answer 33

= square root of 3/2

Question 34

sin(90)

Answer 34

= 1 (square root of 4/2)

Question 35

sin(180)

Answer 35

= 0

Question 36

sin(270)

Answer 36

= -1

Question 37

cos(0)

Answer 37

= 1 (square root of 4/2)

Question 38

cos(30)

Answer 38

= square root of 3/2

Question 39

cos(45)

Answer 39

= square root of 2/2

Question 40

cos(60)

Answer 40

= 1/2 (square root of 1/2)

Question 41

cos(90)

Answer 41

= 0 (square root of 0/2)

Question 42

cos(180)

Answer 42

= -1

Question 43

cos(270)

Answer 43

= 0

Question 44

Equation: Force of gravity in x-direction on inclined plane

Answer 44

F(g)x = m*g*sin(theta)

Question 45

Equation: Force of gravity in the y-direction on inclined plane

Answer 45

F(g)y = m*g*cos(theta)

Question 46

What opposes the force of gravity in the x-direction on an inclined plane?

Answer 46

Tension | Friction

Question 47

What opposes the force of gravity in the y-direction on an inclined plane?

Answer 47

Normal force

Question 48

Equation: Centripetal Force

Answer 48

F(c) = (m * v^2) / r

Question 49

Equation: Centripetal Acceleration

Answer 49

a(c) = v^2 / r | Note: Centripetal Force on a satellite is caused by gravity. Since F = m*a, a=v^2/r (from Centripetal force equation)

Question 50

Equation: Torque at equilibrium

Answer 50

d1 * m1 * g * sin(theta1) = d2 * m2 * g * sin(theta2)

Question 51

transfer of energy by a force acting over a distance change in energy SI Unit: Joule = N*m = (kg*m^2)/sec^2

Answer 51

work

Question 52

If the force applied to a system is ________ to its motion, no work is done.

Answer 52

perpendicular

Question 53

Why is no work done when a force acts perpendicularly to an object's motion?

Answer 53

cos(90) = 0

Question 54

LOSS of E to the surroundings is ______ work being done BY the system and ______ work being done ON the system

Answer 54

positive work done by the system | negative work done on the system

Question 55

GAIN of E from the surroundings is _______ work being done BY the system and ________ work being done ON the system

Answer 55

negative work done BY the system | positive work done ON the system

Question 56

ability to do work scalar measured in Joules

Answer 56

Energy

Question 57

Equation: Kinetic Energy

Answer 57

K.E. = 1/2*m*v^2

Question 58

Equation: Gravitational Potential Energy

Answer 58

U = m*g*h

Question 59

Equation: Work-Energy Theorum

Answer 59

Work(net) = change in Kinetic Energy F*d = 1/2 *m*v^2 Note: d = DISPLACEMENT

Question 60

2 instances where the net work = 0

Answer 60

1. force applied is perpendicular to velocity: cos(90) = 0 | 2. no change in position (displacement = 0)

Question 61

3 examples of conservative forces

Answer 61

electrostatic gravity spring

Question 62

forces that are path independent | state functions that only depend on initial state and final state

Answer 62

conservative forces

Question 63

forces that are path dependent | vary depending on what happens between states

Answer 63

nonconservative forces

Question 64

4 examples of nonconservative forces

Answer 64

air resistance turbulence friction viscosity

Question 65

measures energy expenditure over time increases when max value occurs over shortest amount of time SI unit = Watt = Joule / sec

Answer 65

power

Question 66

an objects tendency to keep moving vector quantity w/ magnitude and direction SI unit = kg*m/sec

Answer 66

momentum

Question 67

Equation: momentum

Answer 67

momentum = m*v

Question 68

For all types of collisions, ________ is ALWAYS conserved

Answer 68

momentum

Question 69

Equation: Conservation of momentum

Answer 69

m1v1i + m2v2i = m1v1f + m2v2f

Question 70

During an __________, energy is lost due to friction, sound, light, configuration changes, etc.

Answer 70

inelastic collision

Question 71

In an ______, energy is lost and objects stick together.

Answer 71

totally inelastic collision

Question 72

Equation: Conservation of momentum in totally inelastic collision

Answer 72

m1v1i + m2v2i = (m1+m2) * vf

Question 73

Elastic collisions lead to final velocities of hte _____ magnitude and ______ direction

Answer 73

same magnitude | final direction

Question 74

Equation: conservation of momentum due to inelastic collision

Answer 74

1/2 * m1v1i^2 + 1/2 * m2v2i^2 > 1/2 *m1 * v1f^2 + 1/2 * m2v2f^2

Question 75

how fast momentum of an object changes | increasing time decreases Force

Answer 75

Impulse