9th Work,Energy and Power
Extra score Questions Q. Can any object have mechanical energy even if its momentum is zero? Explain. Ans: Yes, mechanical energy comprises of both potential energy and kinetic energy. Zero momentum means that velocity is zero. Hence, there it no kinetic energy but the object may possess potential energy. Q. Can kinetic energy of a body be negative? Ans: No, It is because mass and velocity cannot ne negative Q. A freely falling object eventually stops on reaching the ground. What happens to its kinetic energy? Ans: A freely falling object just before hitting the ground has maximum kinetic energy. After falling, it rolls on the rough ground and finally comes to rest. The kinetic energy of the object is used up in doing work against friction; which finally appears as heat energy. Q. A light and a heavy object have the same momentum find out the ratio of their kinetic energies. Which one has a larger kinetic e...