please help, make sure to include all units and draw free body diagrams

$(35$ points total$)$ A winch pulls a $1200$# cart up a hill, as shown. The main shaft of the winch is shown below, simply supported by bearings at A and C$.$ The winch uses a $6^(\text{'}\text{'})$ diameter pulley $($B$)$ and torque is applied at the end of the shaft to pull the cart. Determine the minimum shaft diameter based on the Maximum Distortion Energy $($Von Mises$)$ criterion using a yield strength of $50$ ksi and a design factor of $2\mathrm{.}0.$ If a $6\mathrm{.}5$ HP motor is used to pull the cart, determine how fast the motor is turning