Where do machine get energy from?

Answer 1

Energy is lost through heat transfer. In example: If two parts, lets say gears, move against eachother, they create friction, that friction creates heat.

Cars are estimated to loose somewhere around 70% of their energy I believe. This is because engines produce alot of energy which is lost through heat. Ever notice how hot an engine gets?

Reduce the friction on moving parts can greatly reduce energy loss. Ever notice how much easier to rollerblade with lubed bearings vs old bearings that need lube?

Answer 2

Different machines get energy from different sources. Usually one of the following: (1) electrical energy, from an outlet, (2) electrical energy, from batteries or dry cells, (3) using some fuel, such as gasoline, (4) muscle power.