TBR Physics Ex. 2.11b

[serendipity113]

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If the same experiment were conducted on the Moon, which which exerts a much smaller gravitational force, the slopes of the data curves would:

a. both decrease
b. both remain the same
c. both increase
d. one would increase and one would decrease

There is no answer for this. The experiment is described in example 2.11a for those of who has TBR book.

Ex. 2.11a - an experiment is conducted to test the smoothness of two different horizontal surfaces, A and B. Various mass were slid on these surfaces and the resulting kinetic frictional forces measured.

Explanation would be helpful as well! Thanks!

 

[angldrps]

the answers for the examples that are not given on the same page as the question are all on page 282

 

[MedPR]

Just looked this up in my book and it makes sense. Not sure why I was thinking what I was originally thinking.

This is TTBR 2.12b in the 2011 book. The answer is A.

Explanation: The force due to friction, both kinetic and static, depends on the normal force. Given that the two surfaces are horizontal, the normal force is in equal magnitude to the weight, mg, but in the opposite direction. Because the gravitational force constant on the Moon is less than on the Earth, the frictional force will be less on the Moon than the Earth. This will lower the slopes for both A and B.

The graph is fk on the y axis and mass on the xaxis.

 

[milski]

The only connection I can make with gravity is that the normal will be smaller and the friction will be less than on Earth. The change of friction will affect both surfaces - each will have lower friction force and higher acceleration (compared to the experiment done on Earth). Without knowing exactly what the curves are, there is not much more to be said.

 

[ljc]

The only connection I can make with gravity is that the normal will be smaller and the friction will be less than on Earth. The change of friction will affect both surfaces - each will have lower friction force and higher acceleration (compared to the experiment done on Earth). Without knowing exactly what the curves are, there is not much more to be said.

This was my line of thought. I can't say for sure, but I'd imagine the coefficient of friction would be the same for an object on earth as it would for the same object on the moon. This means as g falls, N falls (N=mg), meaning F falls (F=uN). Friction is less on the moon than on the Earth. Both surfaces should be affected equally. I would guess the answer is A, but not knowing what the curves represent, I can't say for sure.

 

[milski]

I would guess the answer is A, but not knowing what the curves represent, I can't say for sure.

Unless they graphed speeds over time, in which case it would be C. 😉 Agree with the reasoning but it's a lot cause without the graphs.