In order to unscrew the tapped faucet A, a plumber uses two pipe wrenches as shown. By exerting a 40 -lb force on each wrench at a distance of 10 in. from the axis of the pipe and in a direction perpendicular to the pipe and to the wrench, he prevents the pipe from rotating, and thus he avoids loosening or further tightening the joint between the pipe and the tapped elbow C. Determine ( a ) the angle θthat the wrench at A should form with the vertical if elbow C is not to rotate about the vertic