Two identical point masses are attached to the ends of a very light rod of length
PHYSICS · Single correct · A Level · Physics · Engineering physics · Engineering physics
Problem
Two identical point masses m are attached to the ends of a very light rod of length 2L. The rod rotates in a horizontal plane about a fixed central pivot with angular speed ω. The masses are then moved (without external torque) to positions halfway between the center and the ends of the rod (a distance L/2 from the pivot). After the masses are repositioned, what happens to the rotational kinetic energy of the system?
(a) It doubles.
(b) It remains the same.
(c) It becomes four times as large.
(d) It is reduced to one-fourth its original value.