AQA additional physics - Motion

A distance time graph is used to show the distance os a body from a starting point against time taken.

The slope represents speed, the greater the slope the greater the speed.

The speed of a body is the distance travelled each second. We can calculate this by the equation:

Speed (m/s) = distance travelled / time taken.  

The velocity of a body is its speed in a given direction. If the body changes direction it changes velocity, even if the speed stays the same.

If the velocity of a body changes we say it accelerates.

Acceleration(m/s 2) = change in velocity / time taken for the change.

• The slope of a line on a velocity time graph represents acceleration
• The steeper the slope, the greater the acceleration
• If the slope is negative, the body is decelerating
• The area under the line on a velocity time graph represents the distance travelled in a given time