(Solved): A DC circuit involving an ammeter and a DC motor is shown below. A suitable model for the ammeter m ...

A DC circuit involving an ammeter and a DC motor is shown below. A suitable model for the ammeter might include $R_m=1?$ for the galvanometer with a "shunt" resistance, $R_s$ and the motor is modeled as shown where $R_1=60?$ and $V_1=1.4\mathrm{V}$. Suppose we need to keep the galvanometer current $I_m?10\mathrm{mA}$. What maximum value could we use for $R_s?$