# P3

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• Created by: Lauraa01
• Created on: 27-12-13 09:28
What is the gradient on a distance - time graph?
The gradient on a distance - time graph is the speed
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When the gradient is steeper, what happens to the speed?
The steeper the gradient, the higher the speed
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How do you work out distance?
Distance = average speed x time
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How do you work out acceleration?
Acceleration = change in speed / time
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What is relative velocity?
Relative velocity is the difference between the velocities of two bodies having regard to their direction
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What is the area under a speed - time graph?
The area under a speed - time graph is the distance travelled
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What is the gradient on a speed - time graph?
The gradient on a speed - time graph is the acceleration
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What does a negative gradient mean?
A negative gradient means the body is slowing down
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What do forces always occur in?
Forces always occur in pairs that are: the same size, act in opposite directions, act on different objects
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What can forces do?
Forces can make things speed up or slow down
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How do you work out force?
Force = mass x acceleration
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How do you work out weight?
Weight = mass x gravitational field strength
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How do you work out the total stopping distance when a car stops?
Total stopping distance = thinking distance + braking distance
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What does thinking distance depend on?
Thinking distance depends on the state of the driver and the speed of the vehicle (linear)
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What does braking distance depend on?
Braking distance depends on the state of the road, vehicle and speed (squared)
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What do moving objects possess?
Moving objects possess kinetic energy
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How do you work out kinetic energy?
KE = 1/2 mv2
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What does fuel consumption depend on?
Fuel consumption depends on the energy required to increase kinetic energy
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What do roller coasters use as the source of movement?
Roller coasters use gravitational potential energy as the source of movement
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What happens to GPE (Gravitational potential energy) during a roller coaster ride?
During a roller coaster ride, GPE is transferred into KE and back again
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When is work done?
Work is done when a force moves through a distance
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What is power a measure of?
Power (W) is a measure of how quickly work is done
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How do you work out work done?
Work done = force x distance
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How do you work out power (related to rate at which work is done)?
Power = work done / time
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How do you out power (related to force and speed)?
Power = force x speed
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Name three safety features that a modern car has.
Crumple zones, seat belts, air bags
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How do you work out force (to do with cars)?
Force = change in momentum / time
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What can reduce injury?
Spreading momentum change over a long period of time reduces injury
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What do ABS breaks allow?
ABS brakes mean the driver can keep control when breaking without skidding
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What is terminal speed?
Terminal speed is the maximum speed reached by a falling object
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When does terminal speed happen?
Terminal speed happens when the forces acting on the object are balanced
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Why do falling objects get faster as they fall?
Falling objects get faster as they fall because they are pulled towards the center of the earth by their weight
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What is the same at any point on the Earths surface?
The acceleration is the same at any point on the Earths surface
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Two things that forces on a falling object depend on?
The speed of the object (higher speed means more drag), the area of the object (larger area means more drag)
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What happens to its kinetic energy when the car stops?
When the car stops, its kinetic energy turns into heat in the brakes, tyres and road
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Three things that affect reaction time (thinking distance)?
Tired, under the influence of drugs or alcohol, travelling faster
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Three things that affect braking distance?
Poor road conditions, the car has not been properly maintained, the speed is increased
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## Other cards in this set

### Card 2

#### Front

When the gradient is steeper, what happens to the speed?

#### Back

The steeper the gradient, the higher the speed

### Card 3

#### Front

How do you work out distance?

### Card 4

#### Front

How do you work out acceleration?

### Card 5

#### Front

What is relative velocity?