THE FORCES IN NATURE

1. gravitatory force

1.1. wheight of bodies p=m·g

1.1.1. gravity of center

1.2. The law of universal gravitation F= G·m1·m2/d2

1.2.1. aplications

1.2.1.1. movement of planets and satellites

1.2.1.2. tides

2. friction forces

2.1. Is opposed to movements and appears on the surface of contact between two bodies Fr=u·N

2.1.1. Is opposed to movements and appears on the surface of contact between two bodies

2.1.1.1. N=P=m·g

3. electric force

3.1. The electric charge is symbolized with the letter Q and its unit in the SI is the coulomb (C)

3.1.1. types

3.1.1.1. positive

3.1.1.2. negative

3.1.1.3. his intensity is calculated with

3.1.1.3.1. Coulomb law F = K · Q1 · Q2 / d2

3.2. Appears among bodies that have electric charges

3.2.1. attractive

3.2.2. repulsive

3.3. Electric field E = F / Q

3.3.1. lines of forces

3.4. Electrostatic phenomena in the atmosphere

3.4.1. Electric shocks: lightning

3.4.1.1. Measures for their effects

3.4.2. Ionization of air

4. magnetic force

4.1. on magnets

4.1.1. magnetic field

4.1.1.1. lines of forces

4.2. in electric current

4.2.1. electromagnetims

4.2.1.1. Oersted's experiment

4.2.1.2. Faraday's experiment

4.2.1.2.1. electromagnetic inducction