A body is thrown vertically upwards from `A`. The top of a tower . It reaches the ground in time `t_(1)`. It it is thrown vertically downwards from `A` with the same speed it reaches the ground in time `t_(2)`, If it is allowed to fall freely from `A`. then the time it takes to reach the ground.
.
A. `t_(3) =1/2(t_(1)+t_(2))`
B. `t_(3)=sqrt(t_(1)t_(2))`
C. `1/t_(3)=1/t_(2)-1/t_(1)`
D. `t_(3)^(2)=t_(1)^(2)-t_(2)^(2)`
