SOLUTION: A body which is uniformly retarded to rest in 10sec after travelling a distance of 20m calculate the initial velocity

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Question 1144062: A body which is uniformly retarded to rest in 10sec after travelling a distance of 20m calculate the initial velocity


Answer by ikleyn(52890) About Me  (Show Source):
You can put this solution on YOUR website!
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A body highlight%28cross%28which%29%29 highlight%28cross%28is%29%29 uniformly highlight%28cross%28retarded%29%29 decelerates to highlight%28the%29 rest in 10 sec after travelling a distance of 20 m.
Calculate the initial velocity.
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Solution 

Let "a" be the deceleration value (now unknown) and let "t" be the duration of the decelerated move.


Then from Physics,  L = %28at%5E2%29%2F2,  where L is the distance to get stop.


In your case,  L = 20 m, t = 10 seconds,  so


    a = %282%2AL%29%2Ft%5E2 = %282%2A20%29%2F10%5E2 = 40%2F100 = 0.4 m%2Fs%5E2.


Then for initial velocity v,  v = at = 0.4*10 = 4 m%2Fs.    ANSWER