IIT JEE , AIEEE Forum - Physics , Mechanics - Centre of mass: Verma

ramyani

2 persons each of mass m are standing at the 2 extremes of a railroad car of mass M resting on a smooth track.

First, the person on left jumps to left with vel u. Then

-- mu + ( m + M ) V = 0

or, V = mu / (M +m )     is the vel of train plus man towards right.

Now, when the man on the right jumps, the vel of it wrt car is u.

0 = mu - MV¹

or, V¹ = mu / M    towards left.

V is the change of vel of the platform. When the platform itself is taken as ref frame, assuming car to be at rest the above is derived.

Net vel towards left ( i,e, vel of car wrt earth )
                 = mu / M -- mu / (M +m ) = m² u / M (m + M )

whats wrong ?

edited.

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