Energy Conversion

[MedPR]

Confused about a concept, hope you guys can help.

I'm sliding down an incline that is not frictionless. When I reach the bottom of the incline, what can one say about my energy?

A. It was converted from kinetic and potential to thermal
B. It was converted from potential to kinetic and thermal

I'm asking because a question I just did had these two answers and nowhere in the question did it state that I started from rest. So, technically, isn't A plausible since if I was already moving down the incline I had some kinetic energy as well as potential energy since I was some height above the ground? I picked B, just because conventionally we consider things to start from rest, but if it doesn't explicitly say "starts from rest" can we always make the assumption?

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[chiddler]

Confused about a concept, hope you guys can help.

I'm sliding down an incline that is not frictionless. When I reach the bottom of the incline, what can one say about my energy?

A. It was converted from kinetic and potential to thermal
B. It was converted from potential to kinetic and thermal

I'm asking because a question I just did had these two answers and nowhere in the question did it state that I started from rest. So, technically, isn't A plausible since if I was already moving down the incline I had some kinetic energy as well as potential energy since I was some height above the ground? I picked B, just because conventionally we consider things to start from rest, but if it doesn't explicitly say "starts from rest" can we always make the assumption?

I like A more but just because you worded it "i'm sliding down an incline" which suggests that you're not starting from rest. If from rest, then I think is purely potential to thermal if it eventually stops sliding due to friction.

 

[MedPR]

I like A more but just because you worded it "i'm sliding down an incline" which suggests that you're not starting from rest. If from rest, then I think is purely potential to thermal if it eventually stops sliding due to friction.

That's pretty much identical to how the question was worded, but the answer was actually B. I agree with you that A fits the question better as worded, and that's why I'm a little confused (and worried) about how to know what answer to pick.

I'm hoping the real MCAT will make it a point to (at least subtly) indicate starting from rest or already in motion..