It is defined as:
The change in velocity per unit time is called acceleration.
It is a vector quantity because it has a direction. It is denoted by symbol a.
The SI unit of the acceleration is m/s/s or m/s2.
Acceleration occurs when the velocity of an object changes.
The acceleration can be expressed mathematically as,
- v = final velocity
- u = initial velocity
- t is the time it takes to change in velocity.
Zero Acceleration
If a body moves with uniform velocity or constant velocity then its acceleration will be zero.
In the following figure, the car is moving with zero acceleration because there is no change in velocity.
Positive Acceleration
When the velocity of an object increases during the motion, then its acceleration is said to be positive acceleration.
Negative Acceleration
When the velocity of an object decreases during the motion, then its acceleration is said to be negative acceleration.
Negative acceleration is known as deceleration or retardation.