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Forces and Motion

What is a Velocity - Time Graph?

A velocity - time graph shows
how an objects velocity (how fast it is moving) changes with time.

Velocity - Time Graphs for
Constant Velocity and Constant Acceleration.

The picture below shows a velocity - time graph
for an object with a velocity that does not change.

The straight horizontal line in the graph above shows
that the objects velocity does not change as time goes by.
The object is said to have a constant velocity.
Compare this with the distance - time graph for constant velocity.

The picture below shows a velocity - time graph
for an object with a velocity that increases at a constant rate.

The straight line sloping upwards in the graph above
shows that the objects velocity is increasing as time goes by.
Increasing velocity is called acceleration.

What is Constant Acceleration?

The straight line in the graph above shows that
the velocity of the object has a constant acceleration.
This means that the
velocity of the object is changing at a constant rate.

The slope of the line in the graph above shows
1.  the acceleration is positive because the line slopes upwards
2. how fast the acceleration is.
The greater the slope, the faster the acceleration is.

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