Physics 1090 Unit 2: Force and Motion
William Blake’s representation of Isaac Newton: man formed from chaos discovering the order of the physical world

Nature and Nature’s laws lay hidden in night
God said “Let Newton be!” and all was light.
— Alexander Pope, Epitaph for Isaac Newton

He had taught me to notice things. One day when I was playing with what we call an “express wagon” which is a little wagon which has a railing around it for children to play with that they can pull around — it had a ball in it, I remember this, it had a ball in it — and I pulled the wagon and I noticed something about the way the ball moved. So I went to my father and I said, “Say, Pop, I noticed something. When I pull on the wagon, the ball rolls to the back of the wagon; it rushes to the back of the wagon. And when I’m pulling it along and I suddenly stop, the ball rolls to the front of the wagon,” and I say, “Why is that?” And he said that, he says nobody knows. He said, “The general principle is that things that are moving try to keep on moving and things that are standing still tend to stand still unless you push on them hard.” And he says this tendency is called inertia, but nobody knows why it’s true. Now that’s a deep understanding. He doesn’t give me a name. He knew the difference between knowing the name of something and knowing something, which I learned very early.
—Richard Feynman, NOVA #1002, 1983.

Unit Objectives

• Describe motion by words and graphs, and convert between the two.
• Given the velocity at one time for an object on which no forces act, predict its velocity at any other time.
• Given any two of the following properties of an object, find the third: acceleration, mass, net force.
• Explain how changing an object’s mass changes the force exerted on it by gravity.

Class Stuff

• Lab 2 pages from the manual
• PowerPoint presentation unit wrap-up
• Written homework questions for the unit