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a man drops a ball downside from the roof of a tower of height 400 meters.At the same time another ball is thrown upside with a velocity 50 m/s from the surface of the tower,find when and at which height from the surface of the tower the two balls meet together.

Verified Answer :

Case A: Ball dropped downwards
initial vel., v0=0m/s
accl, a=-g=-9.8m/s^2
displacement, S=(x-400) m
Then we have
S=v0t+0.5at^2
x-400= -0.59.8t^2Case B: Ball thrown upwards
initial vel., v0=50m/s
accl, a=-g=-9.8m/s^2
displacement, S=(x-400) m
Then we have
S=v0t+0.5at^2
x-400= 50t-0.59.8*t^2We have 2 eqns:
(x−400)=−0.5∗9.8∗t2
(x−400)=50∗t−0.5∗9.8∗t2
Solving, we get
t=0 & x=400

This is the initial state.... which means that they never meet during the flight...