# Topic 1 & 2 Forces & Motion Flashcards

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1
Q

1 Runner A finishes a race in less time than runner B. Who is faster?

A

runner A

2
Q

2 What two measurements are needed to calculate a speed?

A

distance and time

3
Q

3 What is the SI unit for speed?

A

m/s

4
Q

4 What does acceleration mean?

A

speeding up or slowing down

5
Q

5 What is a force?

A

push or pull

6
Q

6 How do we represent forces on diagrams?

A

arrows, with length depending on size of force

7
Q

7 What does mass mean?

A

amount of substance

8
Q

8 What is the unit for mass?

A

kilogram

9
Q

9 What does a vector have that a scalar does not?

A

direction

10
Q

10 Name a scalar and a vector measured in metres.

A

distance, displacement

11
Q

11 Name a scalar and a vector measured in metres/second.

A

speed, velocity

12
Q

12 Name a vector with units of newtons.

A

force or weight

13
Q

13 Is mass a vector or scalar?

A

scalar

14
Q

14 Is energy a vector or scalar?

A

scalar

15
Q

15 What is acceleration?

A

a change in velocity

16
Q

16 Why is acceleration a vector?

A

it is measuring a change in another vector

17
Q

17 What is the difference between speed and velocity?

A

velocity has a direction/is a vector

18
Q

18 What is the equation for calculating speed?

A

speed = distance / time

19
Q

19 What is the SI unit for speed?

A

metres per second

20
Q

20 What is average speed?

A

total distance / time for whole journey

21
Q

21 What is the equation for calculating distance?

A

distance = speed x time

22
Q

22 How is a constant speed shown on a distance/time graph?

A

straight, sloping line

23
Q

23 What does a horizontal line on a distance/time graph show?

A

stationary object

24
Q

24 What is the speed of sound in air?

A

approximately 330m/s

25
Q

25 How is a stationary object shown on a distance/time graph?

A

horizontal line

26
Q

26 How can you tell which part of a journey shown on a distance/time graph has the highest speed?

A

steepest line

27
Q

27 How can you calculate velocity from a distance/time graph?

A

28
Q

28 What does acceleration mean?

A

change in velocity in time

29
Q

29 What are the units for acceleration?

A

metres per second squared

30
Q

30 In the acceleration equation, what does u stand for?

A

initial velocity

31
Q

31 In the acceleration equation, what does v stand for?

A

final velocity

32
Q

32 What is the equation for calculating acceleration?

A

change in velocity/time, or

33
Q

33 What is the acceleration due to gravity?

A

10m/s2 to 1 sig. fig or 9.8m/s2 to 2 sig. fig.

34
Q

34 What is the force that pulls us towards the Earth?

A

gravity

35
Q

35 What is ‘drag’ another name for?

A

air resistance or water resistance

36
Q

36 What are balanced forces?

A

forces of the same size in opposite directions

37
Q

37 What do we call the forwards force produced by an aeroplane’s engine or propeller?

A

thrust

38
Q

38 What word describes both the speed and direction of movement of an object?

A

velocity

39
Q

39 What is the name for a single force on an object with the same effect as all the forces combined?

A

resultant

40
Q

40 How do we describe the forces on an object when the force in one direction is bigger than the force in the other?

A

unbalanced

41
Q

41 Two forces on an object are in the same direction. How do we calculate the resultant force?

A

42
Q

42 Two forces on an object are in opposite directions. How do we calculate the resultant force?

A

find the difference between them

43
Q

43 What does the length of a force arrow on a diagram represent?

A

size of force

44
Q

44 An aeroplane has thrust of 2000N and drag of 1800N. What is the resultant?

A

200N forwards

45
Q

45 Air resistance on a cyclist is 20N and friction is 5N. What is the total force trying to slow the cyclist down?

A

25N backwards

46
Q

46 Name a vector quantity that changes as a car drives at constant speed around a roundabout.

A

velocity

47
Q

47 What are unbalanced forces?

A

forces of different sizes in opposite directions

48
Q

48 What is the direction of the resultant force on a car that is speeding up?

A

forwards

49
Q

49 What is the direction of the resultant force on a bicycle that is slowing down?

A

backwards

50
Q

50 How does a sideways resultant force affect the velocity of a moving object?

A

changes its direction

51
Q

51 How can the pilot of an aeroplane make the plane gain speed upwards?

A

increase the lift/upwards force

52
Q

52 How do balanced forces affect the velocity of a moving car?

A

The car continues with the same velocity.

53
Q

53 You pedal harder on a bicycle. What happens?

A

you accelerate/get faster

54
Q

54 H What is the name of the force that makes objects move in a circular path?

A

centripetal

55
Q

55 H What provides the centripetal force for a car going around a roundabout?

A

friction

56
Q

56 H What are the forces on a moon orbiting around a planet?

A

gravity acting towards the planet

57
Q

57 H In which direction does centripetal force act?

A

towards the centre of the circle .

58
Q

58 Why is the force of gravity greater on a lorry than on a car?

A

larger mass

59
Q

59 Why is the resultant force accelerating a car usually less than the force provided by its engine?

A

air resistance and/or friction

60
Q

60 Name one force that usually has to be taken into account when working out the resultant force on a moving object

A

drag or friction

61
Q

61 When will a resultant force act to slow a car down?

A

when backwards forces are greater than forwards ones

62
Q

62 How can friction act to make a car speed up?

A

63
Q

63 How can friction act to make a car slow down?

A

in brakes

64
Q

64 What is the formula linking force, mass and acceleration?

A

F = m x a

65
Q

65 An object is moving at a constant velocity. What can you say about the forces on it?

A

balanced

66
Q

66 What is the equation relating these factors?

Speed

Distance

Time

A

speed = distance / time

67
Q

67 What type of force is used to slow down a moving vehicle?

A

friction

68
Q

68 Where is this force applied that slows down the vehicle?

A

brakes, tyres

69
Q

69 Why is a wet road more slippery than a dry one?

A

water acts as lubricant

70
Q

70 An object has a negative acceleration. What does this mean?

A

it is slowing down

71
Q

71 What effect does drinking alcohol have on human reaction times?

A

slows them down/makes them longer

72
Q

72 How will being tired affect reaction time?

A

make it longer

73
Q

73 What does ?braking distance? mean?

A

the distance a car travels while slowing down

74
Q

74 What does ?thinking distance? mean?

A

the distance a car travels while the driver is reacting to a danger and deciding to apply the brakes

75
Q

75 How does speed affect the thinking distance?

A

higher speed, longer thinking distance/thinking distance directly proportional to speed

76
Q

76 How does speed affect the braking distance?

A

higher speed, longer braking distance/braking distance proportional to speed squared

77
Q

77 How does the force needed for an acceleration depend on the size of the acceleration?

A

larger acceleration, larger force needed

78
Q

78 What does deceleration mean?

A

slowing down/a negative acceleration

79
Q

79 H What factors affect the momentum of a moving object?

A

mass, velocity

80
Q

80 H How does the mass affect momentum?

A

higher mass, higher momentum

81
Q

81 H How does the velocity affect momentum?

A

higher velocity, higher momentum

82
Q

82 H What does momentum is conserved mean?

A

total momentum is the same before and after a collision

83
Q

83 What is the resultant force formula?

A

acceleration x mass

84
Q

84 Describe the energy transfers and stores of a skier going downhill to a stop.

A
1. GPE is stored in him at the stop of the slope as well as chemical energy.
2. Falls down the slope, chemical and GPE to KE. Whilst this is happening energy is lost to the surroundings by heat/sound. Dissipates.
3. Coming to a stop all that energy is transferred back to the chemical store.
85
Q

85 The work done by the brakes during braking is equal to the…

A

Energy transferred.

86
Q

86 What is Newton’s 1st Law

A
1. The velocity of an object will only change if there is resultant forces acting on it.
87
Q

87 What is Newton’s 2nd Law?

A
1. Describes the factors that affect the acceleration has on an object.
The acceleration in the direction of a resultant force depends on:
The size of the force
The mass of the object

Defined as Force (N) = mass (kg) x acceleration (m/s^2)
Or F = m x a

88
Q

88 What is inertial mass?

A

The more massive an object is, the more force is needed to change its velocity (easier to make it start moving or to change the velocity of a moving object).

89
Q

89 What is Newton’s 3rd Law?

A

Action reaction pairs of forces. When two objects interact, the forces that they exert on each other are equal and opposite.

90
Q

90 What can we do with action reaction pairs of forces on collisions?

A

They’re the same, but they don’t have the same effects on the two objects, because the objects have different masses.

91
Q

91 Momentum formula and units?

A

Momentum (kg m/s) = mass (kg) x velocity (m/s)
p = m x v

92
Q

92 What does force equal in terms of momentum?

A

Force = change in momentum/time

93
Q

93 What does force equal in terms of acceleration and velocity?

A

Force = mass x change in velocity/time

94
Q

94 What can be used to measure time?

A

Stopwatch (human error)
Light gates for fast moving objects.

95
Q

95 Weight and GFS are directly or indirectly proportional?

A

Directly proportional

96
Q

96 Acceleration and mass are inversely proportional or directly proportional?

A

Inversely proportional

97
Q

97 What is the equation to find the weight of an object?

A

Weight (N) = mass (kg) x gravitational field strength (N/kg)

98
Q

98 Forces of falling objects?

A
99
Q

99 Change per unit/time is also known as what?

A

The rate of change

100
Q

100 Do airbags and seat belts increase or decrease collision time to reduce the change of momentum?

A

Airbags and seatbelts increase the collision time, reducing the rate of change of momentum.

101
Q

101 At greater speeds what are braking and thinking distances?

A

They’re increased.

102
Q

102 How does water being heated by the sun stay at a constant temperature?

A

Heat is lost to the surroundings but then is gained back by absorbing the energy from the sun and the rate of heat loss and heat gained become equal.

103
Q

103 The force in a road collision depends on the change in momentum as the car comes to a stop. What is the equation equal to force that we can use to calculate it?

A
```Force = mv-mu/t
m = mass
v = final velocity
u = initial velocity
t = time taken```