Question

At the height $80\, m$, an aeroplane is moved with $150\, m / s . A$ bomb is dropped from it, so as to hit a target. At what distance from the target should the bomb be dropped ? $\left(g=10\, m / s ^{2}\right)$

• A. 605.3 m
• B. 600 m
• C. 80 m
• D. 230 m

Answer 1

Answer: (A)

605.3 m

Answer 2

Time taken by the bomb to reach the ground is given by
$h_{O A}=\frac{1}{2} g t_{O B}^{2}$

we have $t_{O B}=\sqrt{\frac{2 h_{Q A}}{g}}$
Given, $h_{O A}=80 \,m , g =10\, m / s ^{2}$
$\therefore t_{O B}=\sqrt{\frac{2 \times 80}{10}}=4 s$
Horizontal velocity of bomb $v=150\, m / s$
Horizontal distance covered by the bomb
$A B =v t_{O B}$
$=150 \times 4$
$=600 \,m$
Hence, the bomb-should be dropped $600\, m$ before the target.