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Did you complete the reading assignment? (Typically this means at least 20-30
minutes looking over the assigned sections of the book.)
☐ yes ☐ no
You start to push against a refrigerator. It initially does not budge, but
then after you push hard enough it starts sliding along the floor. Which is correct?
☐ The friction force was smallest just after the refrigerator started to move.
☐ The friction force was largest just after the refrigerator started to move.
☐ The friction force was largest just before the refrigerator started to move.
☐ The friction force was constant the whole time.
A block is sliding down a ramp with constant speed. There is friction between
the block and the ramp. The friction force is:
☐ smaller than the component of gravity down the ramp
☐ larger than the component of gravity down the ramp
☐ equal to the component of gravity down the ramp
A small block is "riding" on top of a large block, which is being pulled to
the right with a rope. Both blocks accelerate at the same rate to the right. The force of
friction acting on the small block is:
☐ to the left
☐ to the right
Ralph noticed that in the
equation for the force of static friction, there's a "less than or equal to"
sign, but in the equation for kinetic friction, there is a plain equals sign. He
wants to know why they are different. What should I tell him?
The comments in the next next two boxes go into a big, mostly anonymous text file that I skim through before the morning lecture, using the comments to help me plan class discussion. ("Mostly anonymous", because I can track down who made what comment, but it takes some effort on my part to do so.) Therefore, if you really want to make sure I see your question/comment and answer it individually, you should send it to me via email and not through this form.
Which part of today's assignment was particularly hard or confusing? What
would you like to spend extra time on in class?
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