***AP Physics 1 Thread 2014-2015***

@mayman I believe so, because he exerts a torque on the system by throwing the ball. Even through its at an angle, there is a component that exerts a torque. The change in Angular Momentum is deltaL=Torque*Time. He increases the angular momentum.

@SimpleBio I believe we’re talking about two different problems. This was one which asked which application of torque maximized angular momentum. The answers were 10 N on the far left going down, 20N on the mid-left going up, and 5 N n the mid and far right going up

@wakaflocka29 why? didn’t the XZ wire have a larger cross section which means different resistance?

@mayman resistivity is different from resistance

@mayman I think angular momentum stays constant; inertia decreases but angular velocity increases.

The MC was hard and the Free Response Questions were just weird. Oh well, I still have IB Physics HL.

@wakaflocka29 but it asked about the resistance not the resistivity

@mayman I remember it asking for resistance as well. I am positive they did.

@mayman ugh i must have mixed up the two then

I’m almost positive it said resistivity

I think it said resistivity

@wakaflocka29 @mayman @chemstar is the problem about the wire bent into a square with one side of it touching a circuit. cause i remember this one being about resistivity.

Form D here. MCQ was very easy to me, feeling a 80-85. As for FRQ… Confident I got 0 points on electricity questions and barely scraped by on experimental design. Feeling low 5, optimistically

It’s resistance, it has to be

It was about the resistivity as I remember it was asking about how the constant p of the wire compared to the resistivity of XZ.

@bobchillax Nope! The XYZ triangle.

Why would they ask about the resistivity?

It was resistivity. I double checked, and it referred to the symbol that looked like “p-nought”, which is RESISTIVITY

Resistivity is a fundamental property of the wire.

So which prep book (Princeton Review/ 5 Steps/ Barrons/ etc…) did you guys think was the best/ had questions with the closest level of difficulty to the test?