Recent content by Curtiss Oakley

Velocity would be constant on a frictionless patch. I don’t see how it could change without any forces acting on it.

Friction is what causes the ball to start rolling without slipping. If there wasn’t any it would roll forever. But after it starts rolling without slipping, that’s the period I’m concerned about.

It for sure would. In my understanding of this question, the frictional force goes with the rotational motion but gravity and friction slows down both the rotational motion and translational motion. Is that fair to say?

That does make sense. So friction would be pulling in the opposite direction I have indicated? The ball would lose tangential velocity in the loop which means it loses rotational velocity in the hoop. That means that the alpha would have to be negative by some force and my only force is...

I already have a and b, but want to see if anyone is willing to verify my answer for part c. I get 0 for the frictional force between the ground and ball, which would lead d and e to be 0 as well. Physics is rarely that easy so I wanted to make sure I didn’t miss anything.

But isn’t torque completely separate from the axis and is instead dependent on the how tangential it is to the circle?

Yes, but I flipped which is postive. Didn’t have to but I did when I first solved it because I mentally saw it as slowing down-making it negative.

The frictional force would oppose my rotational and translational motion, which is my reason for making it negative.

Why change the axis though? To avoid considering a force that you don’t know? Even if you changed the axis, gravity still wouldn’t impact the rotational motion, correct?

That still seems a lot longer than considering both torque and force to solving static friction out. That’s how I worked it out (I attached my work to this reply). I still just feel like I’m missing something.

That sounds overly complicated, especially since the problem didn’t give me anything for t to go off of. If you wanted to do that, how would you start. Maybe I’m missing something.

The only force causing torque is friction. With torque net = r(fs)sin(-90) = I(-alpha)

For parts A and B I used energy to find the vcom and omega, but that won’t work for C. I have an answer by combining the three formulas that use acceleration above. My answer for alpha=-5g/3r. The next two are easily solvable if you find C, but I still feel like I’m missing something. Any help...

Thank you all for the fantastic help! I attached my final answer for any person that may want to get direction and ideas with a similar problem.

I was referring to my answer on the document attached, let me edit my comment to clarify.