A Gate in an Irrigation Canal Is Constructed in the Form

Multiple Choice

A gate in an irrigation canal is constructed in the form of a trapezoid $4 \mathrm { ft }$ wide at the bottom, $8 \mathrm { ft }$ wide at the top, and $2 \mathrm { ft }$ high. It is placed vertically in the canal, with the water extending to its top. Find the hydrostatic force on one side of the gate.

A) $166 \mathrm { lb }$
B) $21 \mathrm { lb }$
C) $67 \mathrm { lb }$
D) $666 \mathrm { lb }$
E) None of these