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Question
A body is moving vertically upwards. Its velocity changes at a constant rate from 50 m s-1 to 20 m s-1 in 3 s. What is its acceleration?
Solution
Here, final velocity = 20 m/s
Initial velocity = 50 m/s
Time taken = 3 s
Acceleration = `("Final Velocity - Initial Velocity")/"time"`
= `(20 - 50)/3` m/s-2
= -10 m/s-2
Negative sign here indicates that the velocity decreases with time, so retardation is -10 m/s-2.
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