A metal sphere of radius R and specfc heat S is rotated abt an axis passng thru its centre at a speed of n rotations/sec. it is suddenly stopped and 50% of the energy is used in increasing d temp., find d rise in d temp of d sphere.

see the kinetic energy of rotating sphere E=0.5*2/5MR^2*w^2 where w is the angular velocity

so when stopped it becomes 0.

so E/2=MsdT(as it is give that 50% of energy is used so E/2)

from here dT=E/(2sM)