Question

what is negative acceleration called

Answer 1

Negative acceleration is also called as Retardation Which is opposite to the positive acceleration.Negative acceleration is also called as De-acceleration.

Answer 2

What is Acceleration?

Acceleration can be defined as the change in velocity per unit time.

What is negative Acceleration called?

Negative Acceleration is called Retardation, or Deceleration.

What does negative Acceleration actually imply?

Acceleration a is given by

$a = \frac{v - u}{t}$

Time can never be negative. So for Acceleration to be negative,

v - u should be negative

v - u < 0

v < u.

So if the velocity of the body is getting decreased over time, It is called Retardation.

Example : We apply brakes to stop the car. When we apply brakes, the car retards to reach 0 velocity and finally stops.