1. Force and Motion-II Applying Newton’s Second Law to More Complex Problems: The Atwood Machine and the Inclined Plane. Lecture 5 Thursday:29 January 2004

2. Applying Newton’s Second Law (F=ma) to more complex problems. Recall,

3. Motion in Two-Dimensions Motion in x direction is completely independent of motion in y direction. Break problem into two parts. One regarding x-motion, one regarding y-motion Each part is then handled just like motion in 1-Dim.

4. A Common Example: Atwood’s machine

5. What do we know? Is tension the same for both masses? Is acceleration the same for both masses? Is the acceleration equal to g?

6. Atwood’s Machine

8. Inclined Plane

9. Problem Solving Tip: Rotate your coordinate system for the inclined plane. Make one axis along the direction of motion. You can leave the coordinate system in the “traditional” form for the hanging weight.

10. N - m 1 g cos  m 2 g  T = m 2 a  m 1 g sin  = m 1 a Add the two equations involving T, in order to eliminate T.

11. Inclined Plane