How can mechanical energy be converted into heat energy?

In different physical processes, mechanical energy can be converted into heat energy in many ways.

First, direct transformation:

1. Friction generates heat or direct impact (such as knocking nails): In the process of friction, atoms and molecules collide with each other, and the vibration intensifies, leading to an increase in temperature. In this process, mechanical energy is directly converted into internal energy.

2. Compressed gas: external force pushes the piston, which makes the gas volume smaller, the pressure increases, the molecular movement intensifies and the temperature rises. In this process, mechanical energy is directly converted into internal energy.

Second, indirect transformation:

In a hydropower station, water drives a generator to generate electricity, and mechanical energy is converted into electrical energy. In users, electricity is heated by heating wires, and electric energy is converted into heat energy.