Computing Internal Energy

[Phantastic]

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Would one ever expect the MCAT to ask a question involving solving for the Internal Energy change of a mass?

For instance, if I said: a 5kg box moving at 10 m/s is brought to a stop by frictional forces on a horizontal plane. The coefficient of kinetic friction is 0.4. (neglect air resistance, etc.)

The MCAT could theoretically ask:

What was the total work done on the box? 250 J using the work energy theorem (W = deltaK)

That seems like a valid question...how about...

What was the total work done by friction? I know we can't just use W=Fd here, because that only comes out to 100J. I take it the other 150J became internal energy? I remember seeing a formula in EK that said:
W = dU + dK + dE(i), aka work is equal to the change in potential, kinetic, and internal energies. That would make the dE(i) 150 J in this case? Am I oversimplifying? So here's my question: Could the MCAT ever ask me to compute dE(i) [change in internal energy] based on the difference in the initial Kinetic energy, and the work done by the frictional force?

 

[Phantastic]

Hmm...after thinking a bit more...

So...since the final velocity is zero, that means dK = -250J, and dE(i_box) + dE(i_plane)= +250J. Is there any way to know how this frictional work of 250J was broken up between the two internal energies of the box and the plane?

I also saw a question recently that gave a person on a slide a final velocity at the bottom, and a starting height. They used the difference in the two energies to compute the work done on the person by the nonconservative force (friction). Is that more like what I can expect?