JEE Mains · Physics · STD 11 - 5. work,energy,power and collision
A ball of mass \(200\,g\) rests on a vertical post of height \(20\,m\). A bullet of mass \(10\,g\), travelling in horizontal direction, hits the centre of the ball. After collision both travels independently. The ball hits the ground at a distance \(30\,m\) and the bullet at a distance of \(120\,m\) from the foot of the post. The value of initial velocity of the bullet will be \(............m/s\) (if \(\left.g =10 m / s ^2\right)\)
- A \(120\)
- B \(60\)
- C \(400\)
- D \(360\)
Answer & Solution
Correct Answer
(D) \(360\)
Step-by-step Solution
Detailed explanation
\(v _1=\frac{30}{\sqrt{\frac{2 h }{ g }}}, \quad v _2=\frac{120}{\sqrt{\frac{2 h }{ g }}}\) \((0.01) u =(0.2) \frac{30 \sqrt{ g }}{\sqrt{2 h }}+(0.01) \frac{120 \sqrt{ g }}{\sqrt{2 h }}\) \(u =300+60=360\,ms ^{-1}\)
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