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Skill 9 of 11
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Known forces

Three main laws of how things move and interact were discovered by Newton. Newton’s laws of motion they are called,[1] but often they are simply referred to as Newton’s 1st, 2nd and 3rd law.1 We’ve seen his first two laws in the Forces 1 course and will meet his 3rd law in the Interaction discipline.

It turns out that Newton’s three laws are all we need to handle forces. Although there exist many different forces with many different origins, they all have the same effect: they either push or pull.[1]

Now, which forces actually do exist? A few are quick to point out:

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  1. Sears and Zemansky’s Univesity Physics with Modern Physics’ (book), Hugh D. Young & Roger A. Freedman, Pearson Education, 13th ed., 2012
  2. Isaac Newton’ (web page), History.com, A&E Television Networks, 2019, www.history.com/topics/inventions/isaac-newton (accessed Jan. 22st, 2020)