Eduprobe
Question:
Two rotating bodies A and B of masses m and 2m with moments of inertia IA and IB (IB>IA) have equal kinetic energy of rotation. If LA and LB be their angular momenta respectively, then
LA=2LB
LA>LB
LB>LA
LA=LB2
Solution:
The kinetic energy of rotation is given by 1/2Iω². Since the kinetic energy of rotation is same, IAωA² = IBωB² ⇒ ωA/ωB = √(IB/IA)
The ratio of the angular momentum becomes,
LA/LB = IAωA/IBωB = √(IA/IB) < 1 ⇒ LB > LA