What is the SI unit of Retardation?

Answer: The SI unit of Retardation (m/s²) meter per second squared.

According to the definition, Acceleration can be defined as the rate of change of the velocity of any object. Retardation is the total opposite of acceleration i.e., negative acceleration.

Retardation can also be called Deceleration; it is mainly the result of the delay. For example: when the velocity of any vehicle is decreasing with time if the brakes are applied.

An expression for finding the acceleration of a body is:

a = (v-u)/t².

Here, ‘u’ is the initial velocity, ‘v’ is the final velocity and ‘t’ is the time taken. If the starting velocity/ initial velocity is more than the final velocity, then it is called Retardation.   

In short, the negative acceleration value denotes retardation.