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# Mechanics 1 Question : Momentum HELP! watch

1. A bullet is fired by a gun which is 4kg heavier than the bullet. Immediately after the bullet is fired, it is moving with speed 200ms^-1 and the gun recoils in the opposite direction with speed 5ms^-1.

Find the mass of the bullet
2. since there is conservation of momentum,
the recoil velocity of gun x mass of gun = mass of bullet x speed of the bullet.
Let the mass of the bullet be m.
3. (Original post by SumOfSquares)
since there is conservation of momentum,
the recoil velocity of gun x mass of gun = mass of bullet x speed of the bullet.
Let the mass of the bullet be m.
Therefore,
5x (4+m) = 200x m
20 + 5m = 200m
20 = 195m
Therefore m = 20/195 kg = 0.10 kg to 2dp
Have you perhaps seem the forum guideline (sticky at the top) about not posting full solutions?
4. (Original post by old_engineer)
Have you perhaps seem the forum guideline (sticky at the top) about not posting full solutions?

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