the mechanical advantage of the wheel - and - belt assembly shown in the illustration is $\frac{1}{3}$. what…

Explanation:

Step1: Recall mechanical - advantage formula

The mechanical advantage (MA) of a wheel - and - belt system is given by $MA=\frac{d_{driver}}{d_{driven}}$, where $d_{driver}$ is the diameter of the driver wheel and $d_{driven}$ is the diameter of the driven wheel.

Step2: Substitute known values

We know that $MA = \frac{1}{3}$ and $d_{driven}=12$ inches. Substituting into the formula $\frac{1}{3}=\frac{d_{driver}}{12}$.

Step3: Solve for $d_{driver}$

Cross - multiply to get $d_{driver}=\frac{12}{3}=4$ inches.

Answer:

C. 4 inches