Question

A body is thrown horizontally from the top of a tower of height $5m$. It touches the ground at a distance of $10m$ from the foot of the tower. The initial velocity of the body is $(g=10m{s}^{-2})$

• A. $2.5{ms}^{-1}$
• B. $5{ms}^{-1}$
• C. $10{ms}^{-1}$
• D. $20{ms}^{-1}$

Answer 1

The correct option is A $2.5{ms}^{-1}$

Height of the tower $H=5m$

Time of flight $T=\sqrt{\frac{2H}{g}}=\sqrt{\frac{2\times 5}{10}}=1s$

Range of projectile is $R=10m$

Initial velocity of projectile $u=\frac{R}{T}=\frac{10}{1}=10m/s$