Hi, this is J. Tech Academy. Today we want to talk about heat and mechanical energy. Heat is a form of energy which flows from one point to another due to temperature difference. Any device that convert heat energy to mechanical energy is called a heat engine. Heat engine works on the following principles. Ah, heat and mechanical work are mutually convertible. Be, energy can neither be created nor be destroyed though and be transformed from one form to another. There are two classifications of heat engine based on combustion process. 1. Internal combustion engine 2. External combustion engine Internal combustion engine The combustion of fuel occurs inside the system. Internal combustion engine is further classified into three, petrol engine or spark ignition engine. Diesel engine or compression ignition engine. And gas turbine engine. External combustion engine The combustion of fuel takes place outside the system. Example, steam turbine. Please, like this video, subscribe for more notification. Thank you.