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A 16 kg bomb initially at rest bursts into two fragments of masses 4 kg and 12 kg. If the 12 kg fragment moves with a speed of 4 m s⁻¹, what is the kinetic energy of the 4 kg fragment?

1. 144 J
2. 288 J
3. 192 J
4. 96 J

Correct answer: 288 J

Solution

By momentum conservation 4*v = 12*4 -> v = 12 m/s. KE = 0.5*4*12^2 = 288 J.

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