Recent content by rbergs215

The later parts of the question involve Point A, not B, but the solution does point to conservation of energy throughout. I'm being pedantic on purpose I guess. Just want to be able to explain this to my students, because they will definitely have the same question. I guess my only problem was...

There's nothing in the problem that states the speed is constant around the loop, so while I understand TSny, and I understand Newton's 2nd Law, still not sure why friction has to be zero. Could there also not be some friction, since the track and loop are not friction-less?

So looking at the solution, FBD for A makes sense: Normal points inwards, gravity and friction oppose each other, with friction pointing up. B confuses me: the solution says there is only Normal and gravity pointing downwards, but if "the sphere rolls without slipping during the entire motion"...