P5- Forces Flashcards

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1
Q

What are scalar quantities

A

Quantities which have magnitude only

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2
Q

What are vector quantities

A

Quantities which have magnitude and direction

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3
Q

What are examples of scalar quantities

A

Mass, temperature, speed, energy

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4
Q

What are examples of vector quantities

A

Displacement, weight, force, velocity, acceleration

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5
Q

What can be used to show the direction of the vector

A

An arrow head

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6
Q

What type of quantity is a force

A

Vector quantity

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7
Q

What is force measured in

A

Newtons

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8
Q

What’s the two types of forces

A

Contact and noncontact

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9
Q

What is a contact force

A

When two objects are physically touching

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10
Q

What are examples of a contact force

A

Tension, Friction, air assistance and normal contact force

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11
Q

What is a noncontact force

A

Two objects are physically separate

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12
Q

What are examples of noncontact forces

A

Gravitational force, electrostatic force and magnetic force

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13
Q

What quantity is mass and why

A

Mass is scaler as it has no direction

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14
Q

Why is weight a vector quantity

A

Because the gravitational field strength causes a force downwards on the object

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15
Q

What is gravitational field strength

A

A measure of the force of gravity in a particular location 

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16
Q

How do you calculate weight

A

Mass x Gravitational field strength

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17
Q

What is the centre of mass

A

The single point where the weight acts on an object

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18
Q

What’s a resultant force

A

A single force has the same effect as all the original forces acting together

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19
Q

How is resultant force measured

A

Taking away the smaller force from the larger force

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20
Q

How do you calculate work done

A

Force x distance

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21
Q

What is elastic deformation

A

When elastic materials return to original size after force has acted on it

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22
Q

What is inelastic deformation

A

When inelastic materials don’t return to original shape when the forces are removed

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23
Q

What equation links force spring constant and extension

A

Force = spring constant x extension

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24
Q

What is a moment

A

The turning effect of a force

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25
Q

How do you calculate moment

A

Force x distance

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26
Q

What is a balance moment

A

When the clockwise moment equals anticlockwise moment

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27
Q

What is a lever

A

It allows large weight to be lifted with relatively small amount of force

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28
Q

What are fluids

A

Gas and liquids

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29
Q

What is the atmosphere

A

A thin layer of air around the Earth

30
Q

What happens to the atmosphere when you increase the altitude

A

It gets less dense

31
Q

What happens to atmospheric pressure with an increase in height

A

The pressure decreases

32
Q

What is upthrust

A

The resultant force caused by the greater pressure on the bottom of the surface then on top of the surface

33
Q

What is distance

A

How far an object has moved

34
Q

What is displacement

A

The distance an object moves in a straight line and in what direction

35
Q

What is a normal walking speed

A
  1. 5 m/s
36
Q

What is a normal running speed

A

3 m/s

37
Q

What is a typical cycling speed

A

6 m/s

38
Q

What factors does speed depend on

A

Age fitness terrain and distance

39
Q

What is velocity

A

Speed and direction

40
Q

Does the velocity change when an object moves at a constant speed in a circle

A

Yes because the direction changes

41
Q

What does a distance time graph show

A

The distance travelled along a straight line

42
Q

What is acceleration

A

The change in velocity over a period of time

43
Q

What does the gradient of a velocity time graph show

A

Acceleration

44
Q

When an object falls towards the surface of the Earth what is the acceleration of the object

A

9.8 m/s

45
Q

What is terminal velocity

A

When an object stops accelerating and moves at a constant velocity

46
Q

What is Newton’s first law of motion

A

If the resultant force acting on a stationary object is zero the object will remain stationary.
Furthermore if the resultant force of a moving object is zero object to move at the same direction and speed.

47
Q

What is newton second law of motion

A

The acceleration of an object is proportional to the resultant force acting on the object and inversely proportional to the mass of the object

48
Q

What is inertia

A

The measure of how difficult it is to change the velocity of an object

49
Q

What is Newton’s third law of motion

A

Whenever two objects interact, The forces they exert on each other are equal and opposite

50
Q
  1. What happens when a skydiver jumps out of the plane
A

The velocity increases as weight is the only force acting on the skydiver

51
Q

Does the weight change during the skydive

A

No the weight Is always the same

52
Q
  1. What happens to the skydiver as it falls
A

The skydiver experiences friction with air molecules the force of friction acts upwards

53
Q

2. As the skydiver falls, why does the diver continue to accelerate

A

The weight is greater than the air assistance

54
Q
  1. What is the effect of the velocity increasing
A

The air assistance increases

55
Q
  1. When does the skydiver reach terminal velocity
A

When the forces balance causing no resultant force and the velocity to be constant

56
Q
  1. When does the surface area of the skydive increase
A

When the parachute opens

57
Q
  1. What is the effect of the parachute opening and increasing the surface area
A

The air resistance increases meaning the result of forces acting upwards so the skydiver decelerates

58
Q
  1. When does the skydiver hit the ground
A

When the weight balances air resistance again but this time at a lower terminal velocity

59
Q

What is the stopping distance

A

The total distance travelled from when the driver spots the obstruction to when the car stops

60
Q

What is the thinking distance

A

The distance travelled by the car during the drivers reaction time

61
Q

What is the reaction time

A

The time taken to spot the obstruction, make a decision and move the foot to the brake

62
Q

What is the breaking distance

A

The distance the car travels from when the driver applies the brakes to when the car stops

63
Q

What’s a typical reaction time

A

0.2 to 0.9 seconds

64
Q

What factors increase reaction time

A

Alcohol drugs tiredness distractions 

65
Q

What factors increase breaking distance

A

Wet or icy conditions, Worn tires

66
Q

What factors increase breaking distance

A

Wet or icy conditions, Worn tires

67
Q

What happens during breaking in a car

A

Friction increases between the brake and the wheel, this causes kinetic energy to convert to thermal energy meaning the temperature increases at the brake

68
Q

How much momentum does a stationary object have

A

Zero

69
Q

What is the conservation of momentum

A

In a close system the total momentum before an event is equal to the total momentum after an event

70
Q

Describe what happens during a car crash in terms of momentum

A

The momentum of the passengers decreases rapidly from large Amount to 0 in less than a second. This places huge forces on passengers

71
Q

How can the danger of huge forces of momentum be decreased

A

By increasing the time of impact

72
Q

What components within a car help to slow down momentum change

A

Airbags and seatbelts