Question

A body is projected upwards with a velocity $u$. It passes through a certain point above the ground after $t_1$ second. The time after which the body passes through the same point during the return journey is

• A. $\frac{u}{g}-t_1^2$
• B. $2[\frac{u}{g}-t_1]$
• C. $3\frac{u^2}{g}-t_1$
• D. $3\frac{u^2}{g^2}-t_1$

Answer 1

The correct option is B $2[\frac{u}{g}-t_1]$

Time taken for upward journey from ground is $t=\frac{u}{g}$

$\therefore$ time for upward journey from this particular point

$=t-t_1=(\frac{u}{g}-t_1)$

$\therefore totaltime=2[\frac{u}{g}-t_1]$