Question

A ball is thrown vertically upwards with velocity of $10\text{m/s}$ from the top of a tower. It returns to ground after some time with speed of $60\text{m/s}$. The height of the tower is

$(g=10{\text{m/s}}^2)$

• A. $375\text{m}$
• B. $175\text{m}$
• C. $125\text{m}$
• D. $225\text{m}$

Answer 1

The correct option is B $175\text{m}$

Let $h$ is the height of the tower.

Taking downward direction as positive.

$v^2=u^2+2as$

$\Rightarrow (60{)}^2=(-10{)}^2+2\times g\times h$

$\Rightarrow h=\frac{3600-100}{2\times 10}=\frac{3500}{20}=175\text{m}$