# P2 AQA Revision Notes

Hope these help

- Created by: Sarah-Jayne Hill
- Created on: 27-02-11 16:38

First 289 words of the document:

Physics 2 Revision

Motion

DistanceTime Graphs

The slope on a distancetime graph represents speed

Speed = distance

Time

The unit for velocity is ms1

Velocity and acceleration

Velocity is speed in a given direction

The acceleration of an object is its change of velocity per second.

Acceleration = change in velocity

Time taken

Deceleration

o Negative acceleration

o Any situation when an object slows down

More about velocitytime graphs

The slope of a the line on a velocitytime graph represents acceleration

When the section of the graph for constant velocity is flat. The line's slope is zero so the acceleration in

this section is also zero.

The line on a graph goes up because the velocity increases with time

The line is straight because the increase in velocity is the same with each second the acceleration was

constant

Using Graphs

For a moving object with a changing speed distancetime graph is not a straight line.

o The slope of the graph increases gradually the object's speed must have increased gradually

To find the distance travelled from a graph area under a velocitytime graph

Speeding up and Slowing down

Forces between objects

Two objects that push or pull on each other exert equal and opposite forces on each other.

Friction acts where an object is in contact with the ground.

Resultant Force

We can work out the effect of the forces on an object by replacing them with a single force resultant

force this force has the same effect as all the other forces acting on it.

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