Recent content by diracy

I'd be interested in the group if it is done online.

Hey all, I'm an undergraduate physics major, thinking about what I want to study in graduate school. Lately, I've been extremely interested in the field of quantum computing. However, I'm not sure what the best background is to do research in this field. Is is physics? Computer science...

If I'm interested in pursuing a theoretical physics PhD, what math courses should I be taking in undergrad and in what order should they be done? I've already taken linear algebra, differential equations, and multivariable calculus, so at a level more advanced than that. I appreciate the help.

any help here?

Homework Statement Consider a wheel of a landing airplane. The wheel has mass M, radius R, and moment of inertia around its axis \alphaMR^2. The wheel lands on the ground with horizontal velocity v, but does not rotate before it touches the ground. (a) Calculate the velocity of the wheel when...

I'm not sure. I've been working on this one for a while, but I haven't gotten very far at all. Any help?

Homework Statement An ideal parachute accelerates all the air it sweeps as it travels, and the air is accelerated from 0 to the parachute's velocity. Using F = dp/dt calculate the force on an ideal parachute of area A as a function of its velocity and the density of air. Assuming you wouldn't...

I got it! I really appreciate the help. I have one more question. How do I show the following: For any three compact sets: A, B, C we have a triangle inequality: d(A, C)\leq d(A,B) + d(B, C)

Edited for a typo.

The \left\ and \right\ should be norm.

Homework Statement Given a compact set A\subset\Re^{n} and a point x\in\Re^{n} define the distance from x to A as the quantity: d(x, A)=inf({\left\|x-y\right\|: y\inA}) Given two compact sets A, B \subset\Re^{n}, define the Hausdorff distance between them to be: d(A, B)=max(sup{d(x, B) ...

Hmmm... After I plug those in, what methods can I use to simply that expression?

Ok, I got the first part. Now I need to prove the angle part. Any help?

I'm honestly not getting very far with this. Could you help me out a little more?

I tried that and didn't get far. It seems to my the leftmost inequality is always equal. I must be thinking about it wrong. In what instance would that inequality be less than?