Motion

A flying bird, Blood flowing through veins, Earth revolving around the Sun

Motion involves change in position with time. A flying bird changes its position, blood flows through the body changing position, and Earth moves around the Sun. A parked car and a book on a table do not change their positions, so they are at rest.

Acceleration is the rate of change of velocity, SI unit of acceleration is m/s², Acceleration can be positive or negative

Acceleration is defined as the rate of change of velocity with time. Its SI unit is m/s². It can be positive (when velocity increases) or negative (when velocity decreases, also called deceleration). Acceleration is not always in the direction of motion - it can be opposite to motion when braking.

A straight line

In uniform motion, equal distances are covered in equal time intervals, so the distance increases at a constant rate. This creates a straight line on the distance-time graph. The slope of this line gives the speed of the object.

Acceleration

The slope of a velocity-time graph represents acceleration. Slope = change in velocity ÷ change in time = acceleration. A steeper slope means greater acceleration, while a horizontal line (zero slope) means zero acceleration.