Question
Tue May 22, 2012 By: Shourya Mukherjee

A car travels linearly with uniform retardation. If the car covers 40m, in the last 2 seconds of its motion what is the velocity of the car at the beginning of the last second? Please explain clearly.

Expert Reply
Fri June 01, 2012
 
v2 - u2 = 2aS
0 - u2 = 2 (-a) 40
 
u2 = 80a
 
a = u2/80
 
Now, in the last second, t = 1 sec
retardation a = -u2/80 m/s2
 final velocity = 0
 
v = u + at
 = u - u2/80 *1
 
u = 80 m/s
 
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