(a) In $\alpha$ decay of, say, a $\frac{226}{88}Ra$ nucleus, show that the nucleus
carries away a fraction 1$/\left(1+\frac{1}{4} A_{\mathrm{D}}\right)$ of the total energy
available, where $A_{\mathrm{D}}$ is the mass number of the daughter
nucleus. [Hint: Use conservation of momentum as well as
conservation of energy.] (b) Approximately what percentage
of the energy available is thus carried off by the $\alpha$ particle
when $\frac{226}{88}Ra$ decays?