Reading:

Cutnell and Johnson, Chapters 6 and 7 (through section 7-2).

Problems for Review:

Reviewing these problems gives you good exposure to this week's main topics, in practice. All solutions are posted on our website |http://www.cc.emory.edu/PHYSICS/Faculty/Benson/141/review.html|. Quantitative solutions are also in the Student Study Guide.

Conceptual:

MCAT review problems 7 and 8 (on website).

Quantitative:

Chapter 6, problems 1, 9, 27, 31, 45, 63.
Chapter 7, problems 1, 5, 9, 17, 45.

Problems to Hand In:

Conceptual:

Use the following to answer questions 1--8:

While walking around a county fair, a group of children comes across a thrill ride in the form of a slide:

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Starting from rest at point I, a child slides down the frictionless slide, traveling over a circular bump of radius R at point II. After passing point III, the child slides over a slightly rough horizontal surface with coefficient of kinetic friction . Sliding over this rough surface is how the child eventually comes to a stop, ending the ride at point IV.

In the following problems, neglect air resistance and take the bottom of the slide to be the level of zero gravitational potential energy.

Between point II and the end of the ride at point IV, the child's energy gets converted from
1. gravitational potential to kinetic
2. gravitational potential to heat
3. gravitational potential and kinetic to heat
4. kinetic to heat
The child must traverse a certain distance over the rough surface to come to a stop. If the slide designers wish to stop the child in half that distance, the work required by friction would necessarily:
1. double.
2. quadruple.
3. remain the same.
4. halve.
As in the previous question, if the slide designers wish to stop the child in half the distance, the frictional force would necessarily:
1. double.
2. quadruple.
3. remain the same.
4. halve.
In getting to the top of the slide, a vertical ladder must be climbed. Suppose two children of the same mass climb the ladder. Child A reaches the top in 30 seconds, while child B takes 1 minute. Compare the power output by both children in climbing the ladder.
As in the previous question, child A and child B, of equal mass, climb the same slide: child A in 30 seconds, child B in 1 minute. Compare the work done by both children in climbing the ladder.
Suppose that as a child slides down the slide we take air resistance into account. The work done by the child on the air can be written as:
1. the change in the child's kinetic energy.
2. the change in the child's potential energy.
3. the change in the child's kinetic energy plus the change in the child's potential energy.
4. the change in the child's kinetic energy minus the change in the child's potential energy.
Suppose the child is traveling too fast when she reaches point II. Which of the following BEST describes her path after passing point II?
After sliding down the slide, a child then travels across the rough surface until coming to rest. Which of the following equations best represents how far the child will travel before stopping?

Quantitative I: