# A body is projected vertically upwards. If $t_1$ and $t_2$ be the times at which it is at height h above the point of projection while ascending and descending respectively. then h is,

$\begin{array}{1 1}(A)\;\frac{1}{2}g t_1t_2 \\(B)\;g t_1t_2\\(C)\;2g t_1t_2\\(D)\;4g t_1t_2 \end{array}$

$h= ut - \large\frac{1}{2} $$gt^2 If the roots of this equation are t_1 and t_2 then using the fact that the product of roots is equal to c/a for the equation ax^2 +bx+c=0 , we get t_1t_2= \large\frac{h}{(1/2g)} \quad h= \large\frac{1}{2}$$gt_1t_2$
Hence A is the correct answer.