A flexible chain of length 3L and mass m hangs over a frictionless pulley so that the length of the vertical parts of the chain on either side of the pulley is L. After a slight disturbance, the chain begins to slide to the right. What is the force exerted by the chain on the pulley at the instant the length of the vertical part of the chain on the right is 3L/2?

Many thanks to all contributors and we hope to hear from many more of you in the future!

Note: as always, we would very much appreciate reader-contributed original Challenges.

Supplementary Material

AAPT members receive access to The Physics Teacher and the American Journal of Physics as a member benefit. To learn more about this member benefit and becoming an AAPT member, visit the Joining AAPT page.