posted by Ethan .
A chain is held on a frictionless table with 1/3 of its length hanging over the edge. If the chain has length L = 33 cm and mass m = 21 g, how much work is required to pull the hanging part back onto the table?
11 cm = 0.11 m hung over the edge, and the center of mass of that part of the chain was 0.055 m below the edge.
The work required to lift it all onto the table would be
W = m g H =
0.021 kg*g*(0.055 m) = ___ joules
0.11 m, so the center of mass of that part of the chain is 0.055 m below edge.
W = mgH = (0.021/3)kg*g*(0.055) = ____J
notice that the kg is different.