Question

An object is thrown vertically upward with a velocity of $10{\text{ms}}^{-1}$ from the ground. It strikes the ground after____ seconds. (Take $g=10{\text{ms}}^{-2})$

• A. $10$
• B. $2$
• C. $5$
• D. $1$

Answer 1

The correct option is B $2$

Given, $u=10{\text{ms}}^{-1},g=10{\text{ms}}^{-2}$
It will strike the ground after completing its flight, so time of flight is given as
$T=\frac{2u}{g}=2\times \frac{10}{10}=2\text{sec}$