Question:
Is there any concept of kinetic energy in gravitation? Why is work done equal to change in potential energy and not change in kinetic energy?
Answer:
There are different forms of energy. Potential energy is associated with mass and position of the body where as kinetic energy is associated with mass and velocity of the body.
The gravitational potential energy is the work done in lifting an object to a certain height against the gravitational force. When the object is at rest at a height, it has only potential energy. When it falls down from a particular height, it gains kinetic energy and losses potential energy. We know that PE = mgh and KE = ½ mv2
Mechanical energy = PE + KE at any point. This energy is always conserved at any point in time.
Kinetic energy comes into picture only when there is a velocity or movement of the body. The body at rest at a height posses only potential energy. This is the reason why we consider change in potential energy in gravitation.
Not what you are looking for? Go ahead and submit the question, we will get back to you.
