Musings are not meant to provide answers. They are meant for stretching thinking muscles.

A simple formulation of law of conservation of energy can be as under:

Energy cannot be created or destroyed, but only changed from one form into another or transferred from one object to another.

A slightly more complex version of this law adds a qualifier:

In an isolated system energy cannot be created or destroyed, but only changed from one form into another or transferred from one object to another.

Musing No 1

A hunter has made a fire in the wilds from the logs found there and is cooking food on it. Later on the hunter will have a coffee and allow the slowly burning logs to provide him heat while he sleeps. How is energy being conserved?

Musing No 2

A pendulum in a perfect vacuum and with its pivot frictionless will go on swinging converting kinetic energy to potential energy and vise versa. Assume that if there is some air in the jar that encloses it and there is some friction at its pivot it comes to a halt in five years time. How has energy been conserved? Easy to answer?!

Musing No 3

In the above experiment the pendulum is made of a magnetic material and there is coil of magnetic wire wrapped around the jar. In how much time will the pendulum come to a halt?

Musing No 4

The coil has LED attached to it. In how much time will the pendulum come to a halt?

Musing No 5

The coil has 5 LEDS attached to it. In how much time will the pendulum come to a halt?