Question

A stone is dropped from a height h. Simultaneously another stone is thrown up from the ground with such a velocity that it can reach a height of 4h. Find the time when two stones cross each other.

Answer 1

For second stone,

but they meth at height H in time t₀ .

∴ Displacement of 1st stone is

and that of second stone is

After solving eqn (1) and (2)