Repeat the previous friction experiments in 7.1 but instead pull the brick so that it moves at a constant velocity.
Notice the reading right before the brick starts moving and right after, keeping it moving but not accelerating.
a) Explain a time when you have experienced this phenomenon before.
b) Draw a force diagram for the brick (the system) for the following situations.
1. The spring pulls on the brick, and the brick is just about to start moving but hasn’t moved yet.
2. The spring pulls the brick at a slow, constant velocity.
c) Summarize the pattern you found. Compare the magnitude of the resistive force just before the brick
starts moving to the magnitude when it is moving at a constant velocity. What do you observe?