A stone is thrown vertically down into a well, the splash is heard after a time t1. If the stone is thrown
vertically up with the same speed from the same point, the splash is heard after a time t2. The common
initial speed (u) of the stone in both the cases is given by (the time taken by the splash sound to reach the
observer is ignored)

A

$$u=g(t_1-t_2)$$

B

$$u=g(t_1+t_2)$$

C

$$u=\frac{1}{2}g(t_1+t_2)$$

D

$$u=\frac{1}{2}g(t_1-t_2)$$