Which type of energy is stored while stretching the catapult? How this energy is obtained?
While stretching the catapult, potential energy is stored in it. This energy is obtained by doing work against the restoring force of the string.
What happens to the kinetic energy when the velocity of a moving body is trippled?
The kinetic energy increases by 9 times when the velocity of a moving body is trippled.
Mathematical expression for Kinetic Energy (KE) = 1/2 m(v)2
When the velocity of body is trippled, new velocity (v') = (3v)
So, new Kinetic Energy (KE') = 1/2 m(v')2
= 1/2 m(3v)2
= 1/2 m(9v2)
= 9 . 1/2 m(v)2
= 9 KE