Liquid to gas, the energy needed per gram is called latent heat of vaporization. Converting heat to mechanical energy. Ideal heat engine is an engine, which can extract the maximum mechanical energy allowed by the second law of thermodynamics. Impossible to build a refrigerator that can remove heat from a lower temperature to a higher temperature without doing work. The entropy of a system always increases or stays the same.
All motion is relative.
This is called the reference system. For example for us the reference system can be fixed on the surface of the Earth, while a space traveler will find it much more simpler to use the Sun as the reference system. In an accelerating elevator, if you stand on a balance, what you read is the normal force. This is a fictitious force. Coriolis force is a fictitious force.