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Question
A racing car is moving with a velocity of 50 m/s. On
applying brakes, it is uniformly retarded and comes to rest in 20 seconds. Calculate its acceleration.
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Solution
Initial velocity of car = u = 50 m/s
Final velocity of car = v = 0 .......[∵ As car comes to rest]
Time = t = 20s
Acceleration = a = ?
v = u + at
0 = 50 + a(20)
−20a = 50
a = `(-50)/20` = −2.5 ms−2
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