# Physics GCSE P2

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Physics Revision

·        Mass weight and gravity

o   Gravity- the force of attraction between all masses

§  -makes things accelerate towards planets- earth= 10m/s^2

§  -it gives everything weight

§  It keeps things in orbit

o   Weight and mass

§  Mass= the amount of stuff in an object

§  Weight =Pull of gravity on that stuff

§  An object has the same mass but a different weight on different planets

§  Weight is a force measured in newton’s

§  Weight= mass x acceleration

o   The three laws of motions

§  1. Balanced forces mean no change in velocity

§  2.a resultant force means acceleration

·        Force=mass x acceleration

§  3. If object a exerts a force on object b than object b exerts the exact same opposite force on object a

·        friction

o   If there is no force propelling an object then friction will slow it down to a standstill

o   Resistance or drag is friction from air or fluids

·        Terminal speed

o   Terminal speed is the speed that a falling object reaches when it stops accelerating

o   As the speed increases so does the resistance until they reach equilibrium

·        Stopping distances

o   Includes two things:

§  Thinking distance which in itself is affected by three things:

·        a) how fast your going

·        b) how dopey you are- depending on how awake you are, drugs, age and how careless you are

·        c)visibility- including weather and eyesight

§  Braking distance- affected by 4 main things

·        a) the speed at which your traveling

·        b) how heavy the vehicle is- a car with loads of people in takes longer to stop then a care with few people in.

·        c)how good the brakes are

·        d)how good the grip is affected by 3 things