Initially the nucleus of radium – 226 is at rest. It decays due to which and a particle and the nucleus of radon are created. The released energy during the decay is 4.87 Mev, which appears as the kinetic energy of the two resulted particles. [mα=4.002amu,mRn=222.017 amu]
Kinetic energies of particle & radon nucleus are respectively
4.08 Mev, 0.09 Mev
3.68 Mev, 0.08 Mev
P=mv and
P22m=12mV2Ea=P22mEradon=P22M
Also
P22m+P22M=ΔE⇒P=√2ΔEmMm+Mm=4.002mu,M=222.017mum=6.64×10−27 kg