Question
Wed May 25, 2011 By: Shreyash Rai Rai
 

when a body is being thrown from rest like i throw a ball from the top of a building then the initial velocity of the ball would be zero but its final velocity has a magnitude, i din't get it the body strikes the ground and comes to rest then the v should have been 0, why do we consider the velocity with which the body strikes the ground???...can it ever be considered to be 0??? are we taking into account the momentum of the body??

Expert Reply
Wed May 25, 2011
When we throw a body from a rest , the body slowly and slowly gain velocity and due to this velocity a body along its mass were able to do some work and if we take velocity to be zero then their won't be any kinetic energy in the body and hence the body will not be in position to do the work.So velocity cant be zero.
But once the body hits the ground and the body come to a rest then we can take its velocity to be zero.
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