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A person holding a rifle (mass of person and rifle together is 100 kg) stands on a smooth surface and fires 10 shots horizontally, in 5 s. Each bullet has a mass of 10 g with a muzzle velocity of 800 ms–1. The final velocity acquired by the person and the average force exerted on the person are
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- –1.6 ms–1; 8 N
- –0.08 ms–1; 16 N
- – 0.8 ms–1; 8 N
- –1.6 ms–1; 16 N
Correct Option: C
According to law of conservation of momentum MV + mnv = 0
| ⇒ V = | = | ⇒ -0.8 m / s | ||
| M | 100 |
According to work energy theorem,
Average work done = Change in average kinetic energy
| i.e. , Fav × Sav = | mVrms2 | |
| 2 |
| ⇒ | = | m | ||||
| 2 | 2 | 2 |
⇒ Fav = 8 N
