A stone falls from rest from the top of a cliff. a second stone is

A stone falls from rest from the top of a cliff.

A second stone is thrown downward from the

same height 3.4 s later with an initial speed of

66.64 m/s. They hit the ground at the same

time.

How long does it take the first stone to hit

the ground? The acceleration of gravity is

9.8 m/s2 .

Answer in units of s