Question

A body is projected upward with a velocity u. It passes through a certain point above the ground after $t_1$. From this instant, the time after which the body passes through the same point during the return journey is

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Suppose v be the velocity attained by the body after time $t_1$. Then

v = u - g $t_1$ .. (i)

Let the body reache the same points at time $t_2$. Now velocity will be downward with same magnitude v ,
then

- v = u - g $t_2$ .. (ii)

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