P$4\mathrm{.}14$ Two construction workers pull on the control lever of a frozen valve $($Figure P$4\mathrm{.}14).$ The lever connects to the valve's stem through the key that fits into partial square grooves on the shaft and handle. Determine the net moment about the center of the shaft.

Figure $\backslash (\backslash$mathbf$\{$P $4.14\}\backslash )$

Details

An illustration shows two forces acting from the handle of a control lever. A force of $300$ Newtons acts downward, and another force of $200$ Newtons acts downward to the left. The angle between the forces is $20$ degrees. The distance between the origin of the forces and the key of the lever is $250$ millimeters.