# GCSE Physics Edexcel P2 Topic 3

These are revision notes I made myself. I got A* in the Physics GCSE exam and 80 UMS (full marks) in the P2 exam using only these notes.

- Created by: aprocrastinator
- Created on: 28-08-13 13:07

First 327 words of the document:

P2 Topic 3: Motions and Forces

Displacement: a straight line from start to finish. It is a quantity with a certain direction as it must go in a

straight line.

Speed: This tells you how quickly an object will travel a certain distance. It can worked out by the following

distance (m)

equation: speed (m/s)= time taken (s)

Velocity: Tells how quickly an object is moving but also which direction the object is moving.

Quantities like displacement and velocity are called vector quantities as they both have a size and a direction.

Force is also a vector quantity. For example, on the Earth the weight of an object is always pulled vertically

downwards.

Distance-time graphs

A graph in which distance is plotted against time is called a distance-time graph. As time and distance are

both used to calculate speed, the graph can tell you a lot of things about speed:

o horizontal lines = stationary object

o straight, sloping lines mean the object is travelling at constant speed

o steeper the line = faster the object is travelling

o Curves represent acceleration and deceleration. Levelling off means slowly down.

o Downhill means going back to its starting point.

o speed can be calculated from the gradient of the line

o distance from the graph

time from the graph

Acceleration

Acceleration: A change in velocity in a moving object. It is a vector quantity as it has a magnitude and a

direction.

Acceleration can be calculated using the following equation: acceleration (m/s2) = change in velocity (m s)

time taken (s)

(v-u)

Or written in symbols: a = t wherein

o a is the acceleration

o v is the final velocity

o u is the initial velocity

o t is the time taken for the change in velocity

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