Question

Then the time taken by the ball to return to the same level is (Take g= 10 ms${}^{-2}$)

• A. 2s
• B. 3s
• C. 4s
• D. 5s

Answer 1

The correct option is B 3s

Here,$u=30m{s}^{-1}$,

$\theta ={30}^{\circ },$

$g=10m{s}^{-2}$
The time taken by the ball to return to the same level is
$T=\frac{2usin\theta }{g}$

$=\frac{2\times 30m{s}^{-1}\times sin{30}^{\circ }}{10m{s}^{-2}}$

$=\frac{2\times 30\times \frac{1}{2}}{10}=3s$