Non-contact Forces
Forces that exist between objects that are not touching, or in contact, are known as non-contact forces. Three non-contact forces are:
Magnetic Force
This is the force experienced by a magnetic object when placed within a magnetic field.
Magnetic elements are iron, cobalt, and nickel.
Opposite poles are attracted to one another…
… but same poles are repelled by one another.
Electrostatic Force
This is the force experienced between charged particles, such as protons and electrons, or ions.
Opposite charged particles attract each other…
… same charged particles repel one another.
Gravitational Force
This force pulls two objects with mass towards each other. Objects in orbit, such as planets and moons, are constantly falling towards each other at speeds so fast they never collide with one another.
If the moon stopped suddenly, it would drop right down onto Earth! Fortunately, it is travelling at a speed too great to simply stop and drop: a wandering moon-sized body would have to directly collide with our moon to stop it in its tracks that quickly.