Recent content by thecommexokid

Hey everybody, Not sure why there was such a sudden resurgence in this thread this week, but my original post was more than 2 years ago. By all means keep discussing the topic if you want, but I have already graduated with the Master's degree I was starting out on when I asked the question.

Cool. I think that clears up my confusion.

Homework Statement A block rests on a table, and a second block, connected to the first with a rope, hangs over the side of the table. See the illustration. (Assume the pulley is massless and frictionless.) All objects pictured are stationary. Identify every force involved in the pictured...

I agree.

Draw a dotted line on your diagram that's exactly halfway between the two walls. Start by focusing only on the part of the particle's trajectory that's between this dotted line and the wall on the right (ignoring for now the other half of the trajectory to the left). Can you use the equations...

PS: I agree with your stated answers for 1–3, except that they are missing units.

Re: 4 You know the speed the car was going when it started braking, the speed when it completed braking, and the distance it took to brake. Can you use those facts to determine the acceleration? Re: 5 You are told the total time for segments 1 and 2, so we only need to figure out how long the...

Perfect, thank you.

I am reading some of "Planck 2013 results. XXII. Constraints on inflation." The paper is full of values for various inflationary parameters under various models, with their confidence intervals. For instance, in Table 5 on page 13, the authors report that — for a model including both running of...

It might help to discuss an examples of how generalized coordinates actually get used in the wild. Consider a system of 1 free particle in 3 dimensions, where I choose spherical coordinates (r, θ, φ) for my generalized coordinates. There are no constraints, so the constraints are trivially...

Not without me being able to find a different frame in which your conversion is no longer time-dependent.

No, I don't mind at all, but this is actually not a different counter-example from your old one, just a more specific case. Here, you have again chosen a frame F = {x}, and then defined frame F' = {x'}, where x' = x – vt. You've just specified that v=–1. So once again, the relationship between...

If I understand correctly, our entire conversation is about the following claim made in the PDF, which I have slightly paraphrased: If the constraints do not explicitly depend on time, then the coordinate transformation which describes the generalized coordinates in terms of the Cartesian...

When the ball is rolling down the trough, it is not pivoting about its center, nor about the center of the trough. It is, at every instant, pivoting about its point of contact with the surface.

What do you mean by "picking another frame relative to mine"? What is "your" coordinate frame? If you have a collection of free particles, there is no intrinsic coordinate frame until you've picked one. For whatever reference frame you choose, the Cartesian coordinates of a point in that...