Newton's Laws Flashcards

1
Q

A hockey puck sliding across the ice finally comes to rest because

A

of friction

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2
Q

When no forces act on moving objects their paths are normally

A

straight lines

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3
Q

A vehicle undergoes acceleration when it

A

changes direction, loses speed, gains speed

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4
Q

Newton’s 1st law

A

inertia

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5
Q

Inertia

A

a tendency to do nothing or to remain unchanged.

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6
Q

If gravity between the Sun and Earth suddenly vanished, Earth would continue moving in

A

a straight-line path.

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7
Q

Which concept is being illustrated when a tablecloth is quickly yanked beneath dishes resting on a table?

A

inertia

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7
Q

Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to

A

follow a straight-line path.

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8
Q

force

A

push or pull

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9
Q

uniform speed

A

constant speed

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10
Q

Acceleration

A

speeds up OR changes direction

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11
Q

normal force/support force

A

force that holds things up. opposite of gravity

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12
Q

speed

A

distance per time

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13
Q

velocity

A

displacement/time

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14
Q

displacement

A

how far an object is moved from one place to another. not distance traveled, distance away, think straight-line

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15
Q

vector

A

direction

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16
Q

magnitude

A

length of vector

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17
Q

instantaneous speed

A

speed measured at instant of measuring

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18
Q

Gravity’s force on Earth

A

10

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19
Q

Freefall

A

an object is in freefall is the only force acting on it is gravity

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20
Q

9.8 m/s2

A

the speed of acceleration of a fall

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21
Q

change in velocity over time
∆v /t

A

acceleration

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22
Q

Newton’s 2nd Law

A

f=ma

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23
Q

kinetic

A

in motion

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24
Q

static

A

at rest

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25
Q

m (mass) *g (gravity) =

A

w (weight)

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26
Q

Newtons

A

measures force and weight (weight is a force)

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27
Q

When a rocket ship gaining speed in outer space runs out of fuel, it

A

no longer gains speed.

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28
Q

A force is a vector quantity because it has both

A

magnitude and direction

29
Q

Does a car’s odometer measure distance traveled or displacement?

A

distance traveled

29
Q

While you are standing in the aisle of a bus, the driver suddenly makes a left turn. You lurch to the right due to

A

your tendency to keep moving forward

30
Q

Does the speedometer of a car measure speed or velocity?

A

speed

31
Q

Suppose you throw a rock straight upward. What is the acceleration of the rock while it is on the way up?

A

9.8 m/s2 downward

32
Q

Suppose you throw a rock straight upward. What is the acceleration of the rock at the very top of its flight?

A

9.8 m/s2 downward

33
Q

Suppose you throw a rock straight upward. What is the acceleration of the rock on the way down?

A

9.8 m/s2 downward

34
Q

True or false: If you get a ticket for speeding, it is based on your average speed, not your instantaneous speed.

A

False

35
Q

True or false: One bullet train travels due north at 220 km/h and another train travels due south at 220 km/h. These trains have the same speed.

A

True

36
Q

True or false: One bullet train travels due north at 220 km/h and another train travels due south at 220 km/h. These trains have the same velocity.

A

False

37
Q

Light travels in a straight line at a constant speed of 300,000 km/s. The acceleration of light is

A

0 km/s

38
Q

True or false: As speed increases for an object in free fall, the acceleration increases as well.

A

False

39
Q

While an object near the Earth’s surface is in free fall, its

A

velocity increases

40
Q

An object at rest near the surface of a distant planet starts to fall freely. If the acceleration there is twice that of the Earth, its speed one second later would be

A

20 m/s

41
Q

If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by about

A

10 m/s

42
Q

A rock dropped from a 5-m height accelerates at 10 m/s2
and strikes the ground 1 s later. If the rock is dropped from a height of 2.5 m, its acceleration of fall is

A

the same

42
Q

A cart changes its speed from 90 m/s to 100 m/s in 10 seconds. During this interval its acceleration is

A

1m/s2

43
Q

A freely-falling watermelon falls with constant

A

acceleration

44
Q

The time it takes a projectile fired straight up at 10 m/s to reach the top of its path is about

A

1 s

45
Q

Whenever the net force on an object is zero, its acceleration

A

is zero

46
Q

If an apple experiences a constant net force, it will have a constant

A

acceleration

47
Q

A 10-N falling object encounters 10 N of air resistance. The net force on the object is

A

0 N

48
Q

A 1-kg mass at the Earth’s surface weighs

A

10N

49
Q

A pair of action-reaction forces always

A

comprise a pair of interactions

50
Q

Two balls are thrown straight up into the air from the same location and with the same speed. One ball has twice the mass of the other. Neglecting air resistance, which ball will achieve the greatest height?

A

neither, they will achieve the same height

51
Q

If a freely falling object were equipped with a speedometer on a planet where the acceleration due to gravity is 20 m/s2, then its speed reading would increase each second by ________

A

20 m/s

52
Q

A mobile phone is pulled northward by a force of 10 N and at the same time pulled southward by another force of 15 N. The net force on the phone is __________

A

5N

53
Q

A heavy truck crashes into a much lighter car. Which object receives the strongest force of impact?

A

the impact forces are equal in strength for both objects

54
Q

The mass of a lamb that weighs about 110 N is about

A

11 kg

55
Q

Compared to the mass of an apple on Earth, the mass of the apple on the moon is

A

the same

56
Q

An apple at rest weighs 1 N. The net force on the apple when it is in freefall is

A

1 N

57
Q

A car traveling on a straight road maintains a constant velocity of 40 m/s for 10 seconds

A

4 m/s2

58
Q

A 2 kg mass at the Earth’s surface weighs

A

20 N

59
Q

A box is being accelerated across perfectly frictionless ice by a 13N force. Suddenly the box encounters a second force of 13N in the opposite direction. With both forces acting on the box it

A

continues at the speed it had when it encountered the second force.

60
Q

When a rocketship gaining speed in outer space runs out of fuel, it

A

no longer gains speed, remaining at a constant velocity.

61
Q

The two measurements necessary for calculating average speed are

A

distance and time.

62
Q

When you walk at an average speed of 4 m/s in 5 s you’ll cover a distance of

A

20 m

63
Q

For an action force, there must be a reaction force

A

that is exactly equal in magnitude

64
Q

Consider drops of water that leak at a steady rate from a dripping faucet. As the drops fall they

A

get farther apart

65
Q

If one object has twice as much mass as another object, it also has twice as much

A

inertia

66
Q

When a rock thrown straight upwards gets to the exact top of its path, its

A

velocity is zero and its acceleration is about 10 m/s2

67
Q

The force of friction on a sliding object is 10N the applied force need to maintain a constant velocity is

A

10N

68
Q

When you rub your hands together, you

A

cannot push harder on one hand than the other.

69
Q

When you walk, you push on the floor to the left and the floor

A

pushes you to the right.