Problem Graphic

After designing an elaborate plumbing system, a plumber's apprentice uses a pipe wrench to tighten the connections. Unknown to him, he is placing unnecessary moments on other parts of the structure that could bend the pipes and lead to leaks or failures.

What is known:

  • The plumber exerts a force of 80 N on the pipe wrench as shown.
  • All of the necessary dimensions are shown.

Problem Description


At which one of the five elbow joints is the moment of the force maximum?


  • For each of the five joints, determine the perpendicular distance to the line of action of the force.
  • The magnitude of the moment is the force times the perpendicular distance, also known as the moment arm.
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