Q.

A goods train accelerating uniformly on a straight railway track, approaches an electric pole standing on the side of track. Its engine passes the pole with velocity u and the guard's room passes with velocity v. The middle wagon of the train passes the pole with a velocity.

1 u+v2  
2 12u2+v2  
3 uv  
4 u2+v22  

Ans.

(4)

Let 'S' be the distance between two ends 'a' be the constant acceleration

As we know v2-u2=2aS

Let vc be velocity at mid point.

Therefore,

vc2-u2=2aS2

vc2=u2+v2-u22

vc=u2+v22