B3-14: EQUILIBRIUM PARADOX - SCALES AND PULLEY

ID Code: B3-14
Purpose: Counterintuitive demonstration involving pulley system
Description: A frame containing the pulley and the lower scale hangs from the upper scale as photographed. The initial weight of the lower scale, pulley, and frame together is about 5 Newtons, as read on the upper scale; initially the lower scale reads zero. With the frame detached, you can exert a force on the scale by pulling on the free end of the rope passing over the pulley. With the frame hanging onto the upper pulley, if you pull gently on the free end of the rope until the lower scale reads 10 Newtons, what will the upper scale read: 5N, 10N, or 15 N? The pictures above reveal the answer.
Availability: Available