Question

A solid sphere and a spherical shell with same mass and same radius but with opposite charge are released from rest on a rough surface which is sufficient to avoide sliding. Our system consists of the solid sphere and the shell. Mark the correct statements for the above system.

• A. Mechanical energy of the system is conserved.
• B. Linear momentum of the system is conserved.
• C. Angular momentum of the system is not conserved about any point.
• D. Center of mass will displace.

Answer 1

Answer: (A), (D)

The correct options are
A Mechanical energy of the system is conserved.
D Center of mass will displace.


F is electrostatic force, $f_1\&f_2$ are friction force.
As $f_1$ is not equal to $f_2$, due to difference in moment of inertias, there is $f_{net}$ on system and hence momentum is not conserved and center of mass will displace. Also work of friction is zero so energy is conserved. Angular momentum is conserved about any point on ground.