The nucleus of a certain atom has a mass of 3.8 x 10-25 kg and is at rest. The nucleus is radioactive and suddenly eject from itself a particle of mass 6.6 x 10-27 kg and speed 1.5 x 107 m/s. Find the recoil speed of the nucleus left behind...
Here we shall use the law of conservation of momentum.
Initial momentum = Final momentum
as the nucleus is initially at rest
Therefore, initial momentum = 0
So, Final momentum = MV+mv=0
velocity of the larger nucleus will be