In the Bohr model of the hydrogen atom, the electron revolves in a circular orbit around the nucleus. If the radius is $5.3 \times 10^{-11} \mathrm{~m}$ and the electron makes $6.6 \times 10^{15} \mathrm{rev} / \mathrm{s}$, find
(a) the speed of the electron, $(b)$ the acceleration of the electron, and $(c)$ the force acting on the electron. (This force is the result of the attraction between the positively charged nucleus and the negatively charged electron.)