Question

A bomb is dropped from an aeroplane flying horizontally with a velocity $469{\text{ms}}^{-1}$ at an altitude of $980\text{m}$. The bomb will hit the ground after a time $(g=9.8{\text{m/s}}^2)$

• A. $2\text{s}$
• B. $\sqrt{2}\text{s}$
• C. $5\sqrt{2}\text{s}$
• D. $10\sqrt{2}\text{s}$

Answer 1

The correct option is D $10\sqrt{2}\text{s}$

Height of the aeroplane from the ground $=980\text{m}$

Using second equation of motion,
$h=u_{y}t+\frac{1}{2}g{t}^2$
$u_y=0$
$\Rightarrow t=\sqrt{\frac{2h}{g}}$
$=\sqrt{\frac{2\times 980}{9.8}}\text{s}=10\sqrt{2}\text{s}$