Problem Graphic

In the previous section, the moment generated by a wrench as analyzed. However, it was determined that the moment changed as the wrench was rotated around the pipe. It is possible that the magnitude of the moment will increase even though the magnitude of the force remains constant.

What is known:

  • The wrench rotates from α = 0° to α = 90°.
  • The force is applied at point Q.
  • The necessary dimensions are given.


Known information

What is the maximum moment generated at joint B as the wrench rotates from α = 0° to α = 90°?


  • Determine the position vector from joint B to point Q for any angle α.
  • Determine the Cartesian components of F as a function of the angle α.
  • Solve for the moment of F at joint B using the vector description of moment.
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