A ball is thrown straight up from the ground with speed . At the same instant, a second ball is dropped from rest from a height , directly above the point where the first ball was thrown upward. There is no air resistance.

Question

Question- Find the value of in terms of and so that at the instant when the balls collide, the first ball is at the highest point of its motion.

Answer 1

A ball is thrown straight up from the ground with speed
. At the same instant, a second ball is dropped from rest from a
height H, directly above the point where the first ball was thrown
upward. There is no air resistance. (a) Find the time at which the
two balls collide. (b) Find the value of H in terms of and g so
that at the instant when the balls collide, the first ball is at the highest
point of its motion.