To calculate the gravitational potential
energy (GPE) of the chain, we need to consider the center of mass of the
portion of the chain that is hanging off the edge of the table and the portion
that is on the table.
The chain has a total length and mass
.
Half of the chain is hanging off the edge
of the table, so the length of the hanging part is , and the other
half is resting on the table.
Gravitational potential energy of the
hanging part
For the hanging part of the chain:
The mass of the hanging part is
proportional to its length, so the mass of the hanging section is
.
The center of mass of the hanging part is
at the midpoint of its length, which is at a height of (since
the hanging part starts from the edge of the table).
The gravitational potential energy for the
hanging part is: