P4 | Mind Map

Car safety features
1. Seat belts stretch slightly, increasing the time taken for the wearer to stop. This reduces the forces acting on the chest.
2. Crumple zones crumple on impact, increasing the time taken for the car to stop
3. Air bags also slow you down more gradually
4. Cycle and motorcycle helmets provide padding that increases the time taken for your head to come to a stop if it hits something hard
Work
1. When a force moves an object it does work and energy is transferred to the object
2. Work done by a force= Force x Distance moved
Forces
1. The resultant force is the overall force acting on an object
2. An interaction pair is two equal forces which are in opposite directions
3. When an object is moving relative to one another, both objects experience a force in the direction that opposes the movement- this is called friction. Friction is a reaction force
Speed, Acceleration and Velocity
1. Speed= distance/ time
2. The steeper the gradient the faster it's going
3. When distance is given with a particular indication of direction it's called displacement
4. Acceleration is the change in velocity in a certain amount of time. Deceleration is just negative acceleration
5. Acceleration= Change in velocity(m/s)/ time taken
6. Velocity describes both the speed and direction e.g 30 mph due north
GPE
1. Change in GPE= Weight x Vertical height difference
2. GPE is the energy stored in an object when you raise it to a height against the force of gravity
3. Falling objects convert GPE into Kinetic energy
Kinetic energy
1. Kinetic energy= 1/2 x mass x velocity squared
2. To increase something's kinetic energy , you need to increase it's velocity

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	Created by Lily Duffy over 8 years ago