Discs A and B are mounted on a shaft XY and may be connected or disconnected by a coupling Z as shown in figure-5.147. The moment of inertia of disc A about the shaft is half that of disc B. The moments of inertia of the shaft and the coupling are negligible. Initially A is disconnected and rotated at an angular velocity `omega`. It is now coupled to disc B using couplings.It is found that 5000 J of thermal energy is developed in the coupling when the connection is made. What was the original kinetic energy of the disc A.

Answer

[7500 J]