A U-238 nucleus originally at rest , decays by emitting an alpha- particle , say with a velocity of vm/s. The recoil (in m/s) of the residual nucleus is.?

Ans: 4v/238

2 answers

work this out with conservation of momentum, the atomic mass of the alpha is 4amu
the mass of the recoiling nucleus is
... 238 - 4

r * 234 = v * 4