Size of the Nucleus

From the relation $R=R_0{A}^{1/3}$, where $R_{\mathit{0}}$ is a constant and $A$ is the mass number of a nucleus, show that the nuclear matter density is nearly constant (i.e. independent of $A$).

Calculate the height of the potential barrier for a head-on collision of two deuterons. (Hint: The height of the potential barrier is given by the Coulomb repulsion between the two deuterons when they just touch each other. Assume that they can be taken as hard spheres of radius $2.0 \mathrm{fm}$.)

Obtain approximately the ratio of the nuclear radii of the gold isotope ${}_{79}{}^{197}\mathrm{A}\mathrm{u}$ and the silver isotope ${}_{47}{}^{107}\mathrm{A}\mathrm{g}$ .