12 4 Universal Forces Part 1

UNIVERSAL FORCES part I

4 Universal Forces:1)Electromagnetic2)Strong Nuclear3)Weak Nuclear 4)Gravitational

Electromagnetic Forces

Electromagnetic force is associated with charged particlesElectric & Magnetic forces = only forces to be able to do both attract and repel.

Electric Forces

Act on Charged ParticlesEX. Protons and Electrons

Opposite charges attractLike charges repel

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Magnetic Forces

Act on: Certain MetalsOn the poles of magnets On moving charges

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Poles of Magnets

Magnets have two poles North & South PoleOpposite poles attract each other—pull closerLike poles will repel each other—push apart

Two Nuclear Forces

1.Strong 2.Weak

Act within the Nucleus to hold it together

Strong Nuclear Force

Powerful force that Acts within the NucleusActs on Protons and Neutrons holding them togetherActs over short distance but is 100 time stronger that Electric Repulsion at same distance

Weak Nuclear Force

Another Powerful force that acts in the nucleus

It is associated with the decay of a nucleus (Breakdown) Is an attractive force that works over a short distance Affects all particles not just Protons and Neutrons.

UNIVERSAL FORCES part 2

Gravitational Force

Gravitational Force:Is the weakest of the Universal forces.It is a force that acts between any two (2) masses.Ex. Like the Earth and Moon, Ex. Like you and the textbook

Newton’s Law of Universal Gravitation

States: Every object in the universe attracts every other object.Gravity is Most Effective over long distanceEX. Gravity Keeps the Sun, Planets, Moons, Stars, Galaxies in orbits in the universe

Mass Determines the ForceGravitational force (GF) depends

upon mass and distance Larger mass =

larger gravitational force

GF Decreases as the distance increases

Earth, Moon & Tides

Centripetal Force – is center directed force.It causes continuous change in direction make it move in a circle.The moon’s mass creates a gravitational force on the Earth causing tides in the ocean.

Tides in the OceanWatch the

tide change with the

phase of the moon!!

Satellites in Orbit and UsesArtificial Satellites are kept in orbit by Centripetal Force Need to keep High speed or Earth Atmosphere will slow it down and it will reenter the atmosphere and burn up.Artificial Satellites are used for Weather,Telescopes, TV, Radio, Cell phone