Q9 of 25 Page 130

When do you say that an object has negative acceleration?

When an object decreases its speed it is said to be undergoing negative acceleration/retardation.

Explanation:


Acceleration is defined as,


Where vf is the final velocity


vi is the initial velocity


t is the time taken


Suppose an object starts with 20m/s from a point A. When it covers a distance of 100m, then, its velocity is decreased to 10m/s.


This is a case of retardation or decrease in acceleration.


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