Question

You slide a coin across the floor, and observe that it slows down and eventually stops. A sensitive thermometer shows that its temperature increased. What can we conclude

Answer 1

The mechanical energy of the coin has been used up in doing work against friction.

Step-by-step explanation:

When two bodies in contact move against one another, friction comes to play. Friction converts energy in such a system to heat which raises the temperature of the body, with most lost to the ambient environment. Sliding the coins on the floor transfers energy from your hand into the mechanical energy of the coin as it moves across the floor. Fiction between the coin and the surface of the floor gradually slows the coin down by converting its energy to heat (which raises the temperature of the coin as detected by the thermometer) until the coin comes to a halt.