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.

Velocity, speed and acceleration are words that we often use to describe motion. We talk about high-speed trains, the acceleration of a sprinter or a Formula 1 racing car. In Physics these words have a precise meaning.

We use words like speed, constant speed, average speed and uniform acceleration to describe different types of motion.

The speed of an object does not require a direction to be considered, it simply has a value and unit, for example, 27 .

Velocity is a vector quantity which requires a value, unit and direction, for example, 49 to the left.

Speed-time graphs can be used to represent motions involving speed and uniform acceleration.

Velocity-time graphs can be used to represent the motion of objects travelling in a straight line, for example backward and forward, up and down, a positive and negative direction.