Question

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

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

Answer 1

The correct option is B $2(\frac{u}{g}-t_1)$

Let the body passes through point A after time $t_1$.
Velocity of body at point A is $v=u-g{t}_1$
Time to reach the highest point is : $t=\frac{u}{g}$
Time to reach the highest point from the point A: $\frac{u}{g}-t_1$
Time to return to point A from point A: $2\times (\frac{u}{g}-t_1)$