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InterviewSolution
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From a rifle of mass `4kg`, a bullet of mass `50g` is fired with an initial velocity of `35m//s`. Calculate the initial recoil velocity of the rifle. |
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Answer» Mass of the rifle, `m_(1) = 4 kg` Mass of the bullet, `m_(2) = 50g = 0.05 kg ` Recoil velocity of the rifle `= v_(1)` Bullet is fired with an initial velocity, `v_(2) = `35 m/s Initially, the rifle is at rest. Thus, its initial velocity, v = 0 Total initial momentum of the rifle and bullet system `= (m_(1) + m_(2))v = 0 ` Total momentum of the rifle and bullet system after firing: `= m_(1)v_(1) + m_(2)v_(2) = 4(v_(1)) + 0.05xx35 = 4v_(1) + 1.75 ` According to the law of conservation of momentum: Total momentum after the firing = Total momentum before the firing `4v_(1) + 1.75 = 0 ` ` v_(1) = – 1.75//4 = – 0.4375 m//s` The negative sign indicates that the rifle recoils backwards with a velocity of 0.4375 m/s |
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