DISTANCE VS TIME GRAPHS WHAT DO THEY MEAN?

Plotting Distance against Time can tell you a lot about a journey Time always runs horizontally. The arrow shows the direction of time The further to the right, the longer time from the start Distance Time

Plotting Distance against Time can tell you a lot about a journey Distance runs vertically The higher up the graph we go, the further we are from the start. Distance Time

If something is not moving Time is increasing to the right But its distance does not change Distance Time

For example, an object which is stopped 30m from the starting point Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

If it is stopped when we start timing, at time zero it will be at a distance of 30m Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 2 seconds it will still be at 30m Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 6 seconds it will still be at 30m Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 14 seconds it will still be at 30m Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

So the graph of an object which is stopped is a horizontal line Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

Consider an object moving with a steady speed (say 3m/s) Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 1 second it will have moved a distance of Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 1 second it will have moved a distance of 3m Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 2 seconds it will have moved a distance of Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 2 seconds it will have moved a distance of 6m Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 4 seconds it will have moved a distance of Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 4 seconds it will have moved a distance of 12m Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 8 seconds it will have moved a distance of Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 8 seconds it will have moved a distance of 24m Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 12 seconds it will have moved a distance of Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

After 12 seconds it will have moved a distance of 36m Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

So the graph of an object moving at a constant speed is a diagonal line Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

Both lines show that each object moved the same distance Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

But the steeper red one got there first, so it must have travelled faster Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

The steeper the line is, the faster an object is travelling Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

An object that is accelerating Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

An object that is accelerating Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

The line is curving upwards The line is curving upwards. This shows an increase in speed, since the gradient is getting steeper Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

Deceleration Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

Deceleration Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

SUMMARY Distance Time

SUMMARY Distance Time STOPPED

SUMMARY Distance Distance Time Time STOPPED

SUMMARY Distance Distance Time Time STOPPED CONSTANT SPEED

SUMMARY STOPPED Distance Distance Time Time CONSTANT SPEED Distance

SUMMARY STOPPED Distance Distance Time Time CONSTANT SPEED Distance ACCELERATING

What’s happening here? Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14

An object which is stopped 30m from the start of it’s journey Distance/m 40 30 20 10 Time/s 2 4 6 8 10 12 14