AP Physics 1 - Units 4 and 5: Models for Interactions

Units 2 and 3 are about describing motion, but in Units 4 and 5 we move in deeper.  I this unit, we will model the causes of motion with a great invention, the force concept.  Why is there a spacecraft to the left?  Thinking about how it behaves can help you understand the force concept.The first piece of the puzzle is understanding why, for instance, the lunar module at the left would continue at constant velocity forever (at least, for a very long time), if it were set on the right trajectory.  The Balanced Force particle model is our first attempt at explaining this behavior.The second piece of the puzzle is understanding why objects exhibit changing motion (i.e., constant acceleration).  The Constant Net Force particle model explains this behavior.After the first test in this unit we will study circular motion and gravitation.