physics
posted by layan .
A stone is dropped into a river from a bridge 41.7 m above the water. Another stone is thrown vertically down 1.87 s after the first is dropped. Both stones strike the water at the same time. What is the initial speed of the second stone?

S=ut(1/2)gt²
S=41.7 m, u=0, g=9.8 m/s²
Solve for t.
Now
S=v0(t1.87)  (1/2)g(t1.87)²
Solve for v0.