12. Define Center of Mass. When is center of mass and center of gravity same? Write the mathematical equation. 13. What are the two condition for equilibrium? Write the equations. 14. What is Moment of Inertia. Write the mathematical equations for point mass. 15. What are the Moment of Inertia equations for a ring, disc, solid cylinder, solid sphere and hollow sphere about an axis passing through center of mass?16. What are the Moment of Inertia equations for rod an axis passing through center perpendicular to its length and about an axis passing at the edge of the rod\"? 17. What is rotational second law of rnotion'iI Write the equation. 13. What is rotational kinetic energy\"? Write the equation. 19. What is angular momentum. When is angular momentum conserved? Write the conservation of angular momentum equation. 9. What is centripetal force? Write the equation for its magnitude and in which direction does it point? Give three different situations and the forces that will provide the necessaryr centripetal force for an object to successfully complete the circular motion