Q. A body of mass $1 k g$ collides head on elastically with a stationary body of mass $3 k g$ . After collision, the smaller body reverses its direction of motion and moves with a speed of $2 m / s$ . The initial speed of the smaller body before collision is ___ $m s^{- 1}$

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Answer: 4

Solution:

Q. A body of mass 1kg collides head on elastically with a stationary body of mass 3kg. After collision, the smaller body reverses its direction of motion and moves with a speed of 2m/s. The initial speed of the smaller body before collision is ___ ms−1