The Derrick - Physics Demonstrations - The Derrick | Physics Undergraduate Labs

Purpose

Demonstrates the trigonometric dependence of torque and tension in static equilibrium. Students see how the tension in a support string changes with angle, and practice applying $\sum \tau = 0$ with adjustable geometry.

Red and yellow meter stick held horizontal by a bench clamp pivot at left end, with a string running from the stick up to a pulley at the top of the vertical rod and across to a large circular Newton force meter dial. A mass hangs from the right end of the stick.

Same apparatus with the string at a steeper angle to the meter stick, changing the geometry. The Newton force meter disc sits on the table below. A mass hangs from the end of the stick.

Figure 1: Derrick apparatus with the meter stick horizontal. The string runs from the stick through the pulley to the Newton force meter, which reads the tension. A hanging mass provides the load torque.

Figure 2: Alternative configuration with a different string angle, showing how the geometry changes the required tension. The Newton force meter disc is visible on the table.

Derrick Meter Stick

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