Torque Wrench, version 2

Mark D. Meyerson, Mathematics Department, U.S. Naval Academy

The tan colored region is the wrench. Grab its point with the mouse pointer and move SLOWLY to adjust its length or position. The wrench can be thought of as turning a bolt at the round end.

The red arrow is the force vector applied to the pointed end of the wrench. By clicking (or dragging) anywhere (except too close to the pointed end of the wrench) you can pick a new starting point for the force vector.

The green sliding rectangle indicates the magnitude of the resulting torque.

There are two black tick marks on the wrench to indicate the scale used for one unit of all of torque, force, and length.

Experiments:

1. Try starting in several different positionings and double the length of the force vector without changing its direction. Approximately what happens to the torque? What if you halve the length?
2. Redo the previous exercise, but change the length of the wrench instead of the vector.
3. Try moving the intial point of the force vector parallel to the wrench so that the component of it perpendicular to the wrench is unchanged. How is torque effected?
4. Leaving the wrench fixed, try to move the force around without changing its length. At aproximately what angle(s) with the wrench for the fixed magnitude force is torque maximized? Minimized?

When you feel you are ready, you can try taking a "homework-quiz" on this material. The results will only be recorded if afterwards you request it. (UNDER CONSTRUCTION!)

The code for the applet above is online.

Here is a picture of an actual torque wrench. Also available are two large pictures of this wrench in use! Mr. Greg Denevan is using it to tighten the valve cover retaining bolts on the 3-71 GMC diesel generator used in a USNA Yard Patrol Craft. Close up view. (Warning: These are BIG files!)