Part III: Identify free-body diagram

Free-Body 1 Free-Body 2 Free-Body 3 Free-Body 4

Please wait for the animation to completely load.

A red block is pushed and moves as shown in the animation.  In addition, a green block sits on the red block and moves as well.  Restart.

  1. What is the acceleration of the two blocks? How do you know?
  2. Which free-body diagram is correct?  Give reasons why the other three diagrams are incorrect.
  3. How would your answer to (2) change if the blocks did not move? 


Problem 4.1, Physlet Physics
2004 by Prentice-Hall, Inc. A Pearson Company