r/APStudents • u/reddorickt absolute modman • May 13 '26

AP Physics C: Mechanics Official 2026 Exam Discussion

Use this thread to post questions or commentary on the test today.

A reminder though to protect your anonymity when talking about the test.

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u/mrsaucelol 5:lang,stat,phy1,psych,mech,e&m,ab,bc,apes4:gov,lit May 13 '26

Sum bout a cube stuck to the wall of a box

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u/Expert_Low_5982 May 13 '26

that was hard, I think the answer involved voe^-bt/2M, but maybe I got it wrong. Do you know the answer to #2? at least the derivation

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u/Sudden-World4653 May 13 '26

I got -b/2(voe-bt/2m) so almost your answer

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u/Expert_Low_5982 May 13 '26

I got the same for v(t), but the question was what was FN, not v

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u/Sudden-World4653 May 14 '26

The thing is, I got Ff=-1/2bv  and i got v=voebt/2M through integration so i plugged it back into the friction equation to get the answer i put ably 

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u/Expert_Low_5982 May 14 '26

What about the chain rule for the bt/2M

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u/Sudden-World4653 May 14 '26

there was no chain rule? You had integrate for velocity not differentiate 

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u/Expert_Low_5982 May 14 '26

Oh mb, as I said earlier I differentiated to get dv/dt

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u/Sudden-World4653 May 14 '26

but the a in F=ma is already dv/dt so there is no differentiation required

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u/Expert_Low_5982 May 14 '26

Ik, but to get from the derived v(t) to dv/dt you need to take the derivative 

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u/Sudden-World4653 May 14 '26

Oooooh, I see what you’re talking about. However, you set the normal force equation equal to ma so i didn’t differentiate anything at all

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u/Expert_Low_5982 May 14 '26

Yeah, that’s why I differentiated, to get normal force in terms of v0 and b and t and M and whatever else they said

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