# P3 OCR Gateway

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• Created by: apple87
• Created on: 30-05-14 13:26
What formual do you get when you combine these two formulas together, Distance = Speed x Time and Average speed = (U+V)/2
Distance = Average speed x time = (U+V)/2 xt
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How do you calculate speed from a distance time graph?
Vertical/horizontal
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On a distance time graph what do all the different lines mean?
Flat sections are where it has stopped. The steeper the gradient the faster it is going. Downhill sections mean it is going backwards. Curves are acceleration or deceleration. Steepening curve is speeding up. Leveling of curve is slowing down.
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What is acceleration?
How quickly soemthing is speeding up?
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On a speed time gaph what do all the different lines mean?
Flat secions are steady speed. Steeper the gradient the greater the acceleration or decceleration. Uphill is acceleration. Down hill is decceleration. The area under any section of the graph is the distance travelled.Curve is non-uniform acceleration
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How do you work out acceleration in a speed time graph?
vertical/horizontal
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How do you work out the distance travelled on a speed time graph?
Equal to the area under the graph
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What is gravity?
The force of attraction between all masses
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What is a reaction force?
From a surface usually acting straight upwards.
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What is thrust or push or pull?
Due to an engine or rocket speeding something up.
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What is drag, air resistance or friction?
Slowing something down
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What is lift?
Due to an aeroplane wing
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Where is tension found?
Rope or cable
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When are all the forces balanced?
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When are the forces unbalanced?
Horizontal acceleration, vertical acceleration
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What three ways does friction occur?
Between solid surfaces that are gripping. Between soild surfaces which are sliding past each other. Resistance or drag from fluids(Liquis or gases eg air)
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What increases friction or drag?
Larger area. Eg roof boxes increase air resistance. Speed
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What factors affect thinking distance?
Speed, tiredness, drugs, alcohol, distractions, lack of concentration, careless blase attitude
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What factors affect braking distance?
Speed, weight of the vehicle, how good the brakes are, how good the grip is this depends on the road surface, weather conditions, tyres.
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What is thinking distance?
The distance the car travels in the time between the driver noticing the hazard and applying the brakes.
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What is braking distance?
The distance taken to stop one the brakes have been applied
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Which does speed affect more braking distance or thinking distance?
Braking distance
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What is the relationship between braking distance and speed?
It is squared
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As speed increases what would a graph showing thinking distance look like?
Linear (a straight line
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As the speed double how many times does the braking distance increase?
4-fold
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If the speed trebles how many times does the braking distance increase?
9-fold
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Define momentum?
The greater the mass of an object the greater its velocity, the more momentum an object has.
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What are most car safety features designed to do?
To reduce the forces acting on the people involved in the accident?
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What safety features increase collision time?
Crumple zones that change shape. Seat belts stretch slightly this reduces forces acting on the chest Airbags also slow you down more gradually.
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How can roads be made safe by increasing the time and distance of a collision?
Crash barriers and escape lanes in dangerous locations
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What do anti lock brakes do?
They help the driver keep control of the cars steering when braking hard. Ordinary brakes would lock the wheels so the driver couldn't turn. They automatically pump on an off to prevent skidding the the wheels from locking. Give shorter braking dist.
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How are safety features tested?
They crash cars containing crash test dummies, both with and without safety features. They analyse slown motion footage. The dummies also have sensors to show how serious an injury would be.
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By what percentage does wearing a seatbelt and having an airbag increase you chances of surviving?
50% for seatbelts and 30% for airbags.
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What things affect fuel consumption?
Larger or more powerful engines. Driving style, weight of the car, amount of air resistance, speed
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Burning them doesn't produce as much pollution, pollution is created during their production. Large areas of farmland need to be cut down to make room for biofuels to grow. Its renewable, amount of CO2 doesn't increase
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They need to be recharged. Electricity is likely to come from power stations that burn fossil fuels. Expensive to buy and make, only go about 100 miles. No pollutants are emitted
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What is power?
How quickly work is being done
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What is work done?
When a force makes an object move energy is transferred
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What is gravitational potential energy?
The energy something has because of its height above the ground. The energy used to raise it is stored.
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What is kinetic energy?
The energy of something when it is moving.
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What does kinetic energy depend on?
Mass, speed
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What does doubling the mass to to kinetic energy?
It doubles
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## Other cards in this set

### Card 2

#### Front

How do you calculate speed from a distance time graph?

#### Back

Vertical/horizontal

### Card 3

#### Front

On a distance time graph what do all the different lines mean?

### Card 4

#### Front

What is acceleration?

### Card 5

#### Front

On a speed time gaph what do all the different lines mean?