1. Universal Forces
12.4 Notes

2. Electromagnetic Forces
Consist of Electricity and Magnetism
Electric Forces – act between charged objects or particles. (protons & electrons)
Magnetic Forces – act on certain metals. Magnets have poles with opposite charges.

3. Electromagnetic Forces
Acts on charged particles like Protons and Electrons

5. Nuclear Forces Forces within an atom
Strong Nuclear Force – hold protons together inside the nucleus
Is “strong” because like charges repel. It takes a lot of force to hold a bunch of (+) charges together.
Weak Nuclear Force – holds the atom together.

6. Strong Nuclear Holds Protons and Neutrons together
Works over a very short distance
Holds Quarks together

7. Weak Nuclear Works with radioactive decay
Works over a very short distance
Acts on all particles
Source of sun’s power

8. Gravitational Forces Newton’s Law of Universal Gravitation.
All object in the universe are attracted to each other by the force of gravity.
The force depends upon the masses of the objects and the distance between the objects.

9. Gravity between Earth and Moon causes ocean tides