Phy 201
Your 'cq_1_21.2' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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A typical automobile coasts up a typically paved incline, stops, and coasts back down to the
same position.
When it reaches this position, is it moving faster, slower or at the same speed as when it
began? Explain
answer/question/discussion:
This would be the same as throwing the ball up in the air. The acceleration of gravity would
be slowing it down as well as speeding it up when it coast back down the incline
That would be the case if no friction was present.
This can be reasoned from the equations of motion or from the work-energy theorem. The arguments used on the preceding cq question can be easily adapted to this situation, as you already see. The following statement summarizes the main idea:
For a real-world automobile friction would oppose motion at every position except the extreme position (where it stops for and instant), doing negative work on the automobile and causing a decrease in its KE. It would therefore end up moving more slowly than at the beginning.
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5min
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