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speed - how fast you are going (direction doesn't matter).

velocity - the speed in a given direction

Both speed and velocity are measured in m/s.

they both tell you how fast you are going.

A distance time graph shows the distance travelled over time.

The slope of the graph is called the gradient.

the gradient of the distance time graph tells you how fast your object is travelling.

flat sections is when the object is stationary, it has stopped.

straight uphill or downhill sections means that it is travelling at a constant speed.

the steeper the graph the faster it's going.

downhill means that it is going back to starting point.

curves show a change in speed.

a steepening curve shows a that it's speeding up - this is acceleration

a levelling off curve means it's slowing down - this is deceleration

acceleration is how quickly the velocityis changing.

a change in velocity is can be a change in speed or direction or even both.

Acceleration (a) = Change in velocity (v - u) / time taken (t)

acceleration is measured in m/s^2

the gradient of a velocity -time graph tells you the acceleration of the object.

Flat sections shows the object is travelling at a steady speed.

uphill sections show acceleration

downhill sections show deceleration

the steeper the graph the greater the acceleration or deceleration.

a curved graph means that the object has a changing acceleration.

Gravity is the force that attracts all masses

You only notice it when one of the masses is really big, e.g. a planet.

Gravity makes all things accelerate towards the ground.

Objects fall with the same acceleration

It gives everything a weight.

mass is the amount of stuff in an object. The mass never changes.

weight is caused by the pull of gravitational force.

weight (W) = mass (m) X gravitational feild strength (g)

The resultant force is the overall force on am object.

A resultant force means a change in velocity.