A circular disc of mass M and radius R is rotating about its axis with angular speed . if the another stationary disc having radius and same mass M is dropped co-axially on the rotating disc. Gradually both the discs attain constant angular speed . The energy lost in the process is p% of the initial energy. Value of p is_________
Option: 1 10
Option: 2 20
Option: 3 30
Option: 4 40
Let the moment of inertia of bigger disc is
by angular momentum conservation
initial kinetic energy =
final kinetic energy
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