cq_1_72

phy121

Your 'cq_1_7.2' 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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An automobile rolls 10 meters down a constant incline with slope .05 in 8 seconds, starting from rest. The same automobile requires 5 seconds to roll the same distance down an incline with slope .10, again starting from rest.

• At what average rate is the automobile's acceleration changing with respect to the slope of the incline?

answer/question/discussion:

Auto 1: Auto 2:

vAve = ‘ds/’dt vAve = ‘ds/’dt

vAve = 10 m /8 sec vAve= 10 m/5 sec

vAve = 1.25 m/s vAve = 2 m/s

vf = 2(1.25 m/s) vf = 2(2 m/s)

vf = 2.5 m/s vf = 4 m/s

a = 2.5 m/s / 8 s a = 4 m/s / 5 s

a = .3125 m/s^2 a = .8 m/s^2

Now, we take the change in acceleration and divide it by the change in slope:

(.8 - .3125 m/s^2) / (.10 - .05) = .4875 m/s^2 / .05

The acceleration changes 9.75 m/s^2 for each degree of change in slope.

Excellent. It's hard to improve on your statement, but consider the following slight changes in wording:

The acceleration changes 9.75 m/s^2 for each unit of change in ramp slope.

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10 min

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Your work is great. See my one note.