Forces

1. Gravity

1.1. Weight

2. Muscles

2.1. Farmer ploughing

3. Wind

3.1. Windmill

3.1.1. Electricity

3.1.2. Ground wheat

3.1.2.1. Flour

4. Mechanical force

4.1. Water mill

4.1.1. Electricity

4.1.2. Ground wheat

4.1.2.1. Flour

5. Pressures of gases

5.1. Gasoline engine

5.1.1. Movement

5.2. Diesel engine

5.2.1. Movement

6. Caused by the effects of heat

6.1. Steam engine