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4
Forces
4.1 THE FUNDAMENTAL FORCES
What is a force? One answer is that it is a push or a pull. A better answer, that we will
nd to be more useful, is that it is an interaction between two or more objects. For
most of our discussion, two objects will suf ce.
Forces are no strangers to us since we interact with all sorts of things every day.
Below is a list of forces I have compiled. Before reading my list, it would be instruc-
tive for you to take out a piece of paper and make your own list. Hopefully you will
come up with some not on my list.
Gravity Electric Weak nuclear Strong nuclear Centrifugal
Magnetic Centripetal
Friction
Wind force
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