Recent content by samtouchdown

Here. Please tell me if the image is of bad quality.

Chirag B: I don't understand how they take it to be upward. Fspring=-kx always. In this case, they define up to be positive and down to be negative. Suppose, the spring is stretched 2 m, then the displacement vector is obviously=-2i. So, then this "kx", which they use, would yield -2k, still...

But they do kx-mg in the princeton review.

Coordinate System--Spring Vertical Hi! This is a question on the use of a coordinate system. In the princeton review, I don't understand the coordinate system they are using it; it doesn't make sense. That is, for a vertical spring, the net force on the mass is kx-mg. But, shouldn't it be...

Well, the unsecured load will fall off the truck. So, to keep the the object on the accelerating truck, we would need friction. So, the friction keeps the object "accelerating" with the truck. I think what's confusing me is how it is accelerating; specifically, it is at rest on the truck but...

Not intuitive--friction causes motion? Hi. I'm having difficulty conceptualizing this situation: Consider two objects, mass 1 and mass 2. Mass 2 is on mass 1 and mass 1 is being pulled by a rope. There is a frictional force between mass 1 and mass 2, but none between mass 2 and the surface...

Hello. I am having trouble conceptualizing and/or decisively arriving to a conclusion to this question. When finding the area enclosed by a closed polar curve, can't you just integrate over the period over the function, for example: 3 cos (3θ), you would integrate from 0 to 2pi/3? It intuitively...

I am wondering if this is solvable. Determine the convergene/divergence of the sum from n=1 to infinity of sec(n)/n. All the tests appear to fail and listing out the sequence of partial sums produces no useful results.

This problem's solution has been widely debated for its validity. Though it gives the correct answer, many argue that it is invalid. Please give comments on why this method works and if it is valid or not. If possible, please provide your own solution. The problem is in the attachment.