posted by Mike .
A block of mass m sliding on a frictionless table is attached to a string that passes through a narrow hole through the center of the table. The block is sliding with speed v0 in a circle of radius r0. (Use any variable or symbol stated above as necessary.)
Find angular momentum of the block
Find kinetic energy of the block
Find the energy of the string
A student under the table now slowly pulls the string downward. How much work is required to reduce the radius of the circle from r0 to r0/2?