Question

An object is projected upwards with a velocity of $100\text{m/s}$. It will strike the ground after

• A. $10\text{sec}$
• B. $20\text{sec}$
• C. $15\text{sec}$
• D. $5\text{sec}$

Answer 1

The correct option is B $20\text{sec}$

As per the question, time of flight is been asked, which is given as
$T=\frac{2u}{g}$
$\Rightarrow T=\frac{2\times 100}{10}$
$\Rightarrow T=20\text{sec}$