Question

a train moving with a velocity of 20 m/s is brought to rest by applying brakes in 5 s calculate the retardation

Answer 1

Heya!
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◾Given that ,
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Initial Velocity U = 20 m/s

Time t = 5 seconds

Final velocity V = 0 [ Bought to Rest

Retardation = ?

⭐Using the first equation of motion,
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V = U + AT

20 + 5A = 0

20 = -5 A

A = -4 m/s²


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Answer 2

retardation (negative acceleration)=velocity × time
=20×5
=100m/s^2