Edwin Hubble was born in Missouri in the year 1864. He was an athlete and an astronomer. It was for his work in astronomy that Edwin became famous.

Applying the Doppler effect to the light coming from galaxies he discovered that more distant galaxies have a larger recessional velocity than nearby ones.

His discovery led onto the fact that space between the galaxies is expanding.

Here are some motion graphs you are expected to know at a glance.

The motion graph of this object tells us that its velocity is increasing at a constant rate.

This means that it is accelerating. The objects acceleration can be found by calculating the rate of the velocity.

The rate of velocity is just the gradient of the graph. This gradient of the velocity time graph is the acceleration of the object.

From the graph the object has an acceleration of 0.5 m s-2

In other words the object`s velocity is increasing by 0.5 m s-1 every second.

Click the tv to see how to calculate the acceleration of the object.

Take a look at this velocity time graph.

In this graph the object accelerated at 2 m s-2 for the first two seconds and then moved with a constant velocity of 4 m s-1 for 4 seconds.

Finally the object decelerated at 1 m s-2 for 4 seconds until it came to rest.

Deceleration is now considered as negative acceleration.

So strictly speaking in the last four seconds the objects`s acceleration was - 1m s-2

Click the tv to see how to analyse the velocity time graph

Acceleration time graphs from velocity time graphs

Physicists like to see the accelerations that happened during an objects motion.

Velocity time graph

Corresponding acceleration time graph

Click the tv to see how to convert a velocity time graph into an acceleration time graph.