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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?
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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
The negative sign here indicates that the velocity decreases with time, so retardation is 10 m/s−2.
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