Revise: Velocity-time graphsVelocity-time graphs

Velocity-time graphs are used to describe the motion of objects which are moving in a straight line. They can be used to show acceleration and to work out displacement.

Part ofPhysicsRevision guides: Dynamics

Velocity-time graphs

Velocity-time graphs are used to describe the motion of objects which are moving in a straight line. The object may change direction, eg from forward to backwards, up or down, left or right.

Velocity-time graphs are similar to speed-time graphs.

The following velocity-time graph represents the motion of a bus which travels along a straight road, then returns in the opposite direction.

The positive section of the graph represents the forward direction; the negative section represents the opposite direction.

Velocity (ms-1) against time (s). Accelerates from origin, constant, decelerates to negative, constant and accelerates to origin. Graph positive (forward direction) graph negative (opposite direction)
Velocity-time graph

Displacement is calculated by subtracting the negative areas of the graph from the positive areas.

Velocity (ms-1) against time (s). Accelerates from origin, constant, decelerates to negative, constant and accelerates to origin. Areas shaded 36m2 (+) and 35m2 (-)

Therefore displacement \(= 36 - 35 = 1 m\) in the positive direction.

Next up
Test your understanding
Previous page
Speed-time graphs

More guides on this topic

Related links