@appgodxoxo Is your teacher predicting that based only off the 2015 FRQs? I think that curve sounds about right, except the curve for a 3 might be higher than 35%( maybe like 39%).
Waiting until July for the score will be painful, especially because I made a few mistakes on the FRQ. That’s why I try to avoid looking at the answers some people came up with so I can avoid stressing about my score.
I made a lot of mistakes on the FRQ as well. If you’d like, I can send you the answers to the FRQ that a teacher (nt mine) has released so you can check. PM me.
Here is the FRQ answers… again this was not made by my teacher but rather I think a student, so it could be wrong.
imgur --> /a/6OrLu
I believe the Biot savart law is incorrect on the ap formula sheet… thats sorta kinda a huge problem. you know. not that it was needed or anything and that thousands of people might have missed a big part of a question because it was wrong on the formula sheet. No biggie
Did anyone else not have a velocity-time graph for question 4 (projectile motion of sphere A and B) on the FR?
For #5a in the FRQ, would it be correct to say the tension changes in the 4 strings? I know people have been saying density, but doesn’t tension work as well, since the equation is v= sqrt tension/(m/L)?
Tension isn’t different in the strings. It’s the same length of stretched string.
@twzelle
@twzelle Unfortunately, tension is the same for all strings since an identical mass is hanged at the bottom for all of them. Mass, however, is different.The only correct answers(i think) were mass or density.
Actually, the correct answer is “mass density.”
Not mass or density…
@appgodxoxo Fundamental frequency for a string held at both ends is given by f = v/2L . In this case, the length is the same for all. v = sqrt(Tension/(mass/length)). Both length and tension are the same for all the strings, so with the fundamental frequency being different, the mass of the strings also has to be different.
Err, no.
It says “The distance between each oscillator and pulley L is the same”
The TOTAL length of the string, which constitutes linear mass density, can be different. The mass can be different. The mass AND length of the strings MUST be different.
Thus, the thing that is different about both strings is m and L. Aka, linear mass density
@AlphaDragon
@appgodxoxo why does the length have to be different? If the masses were different for all of them, that would also change linear mass density since it is m/L and if mass changes, then the density also has to change because it is altering the “m” in m/L.
Length is constant for all strings… the section that oscillates is what’s between the pulley and the oscillator, not whatever hangs over. So only mass can affect linear mass density.
@Kyuutoryuu
I’m guess your teacher didn’t explain how the two L’s differentiate then.
With linear mass density, you need to take the TOTAL length of the string into account.
Not just the length that’s oscillating, which can be called the length of “stretched string.” This is where tension is formulated, and why it’s constant across all the strings.
The linear mass density differs across all the strings. The total length and mass can both be different.
Source: my physics teacher. who has helped write the official scoring guidelines for AP Physics B.
How many points would part c of number 5 be worth? I hope it’s only 1 point since I didn’t mark anything…
@appgodxoxo Why does the length necessarily have to be different? The question asked for what could be different in all the strings that could cause a difference in fundamental frequency. If mass were different, that would be enough for the strings to have different fundamental frequencies.
@AlphaDragon
It doesn’t have to be different, but it CAN be different
is there any way to find the correct answers to the free response questions?
Hi guys I am writing the late AP Physics 1 exam so I was just wondering if anyone used five steps to a five, how was the difficulty of the real AP exam compared to the questions asked in the book?
@appgodxoxo Perhaps you’re right. We’ll see in July.
@yolomaster98 the book was slightly easier but it’s still the best out there in my opinion