A $50$ kg drum $\backslash ((80\backslash$mathrm$\{$~cm$\}\backslash )$ OD$,60$ cm ID$),$ is required to spin at $100$ rpm $.$ If you are using a $(11\mathrm{.}4$:$1)$ gear reducer, what is:

a$)$ RPM of the motor $(\backslash (85\backslash \%\backslash )$ efficiency$)$

b$)$ Reflected inertia of the load on the motor

c$)$ Energy required of the motor