A ball is dropped from the top of a building at t=0. At a later time t=t0, a second ball is thrown downward with an initial speed v0. Obtain an expression for the time t at which the two balls meet.
[v0−gt02v0−gt0]t0
When the balls collide at time t=t, the distance covered by them are same. But the caution is that the first ball has moved for t time, while the second has moved for (t−t0) time.
∴12gt2=v0(t−t0)+12g(t−t0)2
After simplifying, we get, t=[v0−gt02v0−gt0]t0