Question

A bullet strikes a stationary ball kept at a height as shown. After collision, range of bullet is 120 m and that of ball is 30 m. Find initial speed of bullet. Collision is along horizontal direction.
(Take g = 10 m/s2)

• A. 150 m/s
• B. 90 m/s
• C. 240 m/s
• D. 360 m/s

Answer 1

Answer: (D)

360 m/s

Answer 2

$m_1V+m_2(O)=m_1v'_1+m_2V'_2\ \ \ \ \ .....(1)$
$\Delta t=\sqrt{\frac{2h}{g}}=2s\ \ \ \ .....(2)$
$⇒v'_1=\frac{120m}{2s}=60\ m/s$
$\&\ v'_2=\frac{30m}{2s}=15\ m/s$
$⇒$ v = 360 m/s

So, the correct answer is (D) : 360 m/s