Recent content by danielhep

Thank you for your help! I think I just needed to get by those barriers and now I understand these problems better. I'll keep strategy b in mind, but I think I might stick to the slightly harder way for now just to make sure I get it.

1) Okay, so what I'm getting is (0,1), (0,-1), (1,0), (-1,0). Plugging these points back in, the maximia is 2 and the minima is 1. I don't think ##\lambda = 1## is important, since it seems that when I do that, it implies x can be whatever and y must be zero, which gets me points that I've...

1) x=0. Then I can plug that back into g(x,y) and get (0,1). Then do the same thing for y and get (1,0). Then I can check those and find which is max and min? Is that correct? Does the 2 coefficient on 2y2 just go away completely? 2) What would be a better way? I just am following the steps I...

Homework Statement Find any maxima/minima on f(x,y) = x2+2y2 on the unit circle, centered at the origin. Homework Equations grad f = λgrad g constraint: 1=x2+y2 The Attempt at a Solution grad f = 2xi+4yj grad g = 2xi+2yj 2x=λ2x 2y=λ4y How do I solve this? I don't see any way to get numbers...

I dropped the g. Thank you so much! I found the correct answer.

Homework Statement A string is wrapped around a uniform solid cylinder of radius r, as shown in (Figure 1) . The cylinder can rotate freely about its axis. The loose end of the string is attached to a block. The block and cylinder each have mass m. Find the magnitude α of the angular...

Fixed the original post, thanks. a represents the y component of the acceleration... Which means I'm just finding the y component of the electric field... I just took my answer and used the pythagorean theorem to find the total magnitude and it was correct! Thank you! That was a perfect hint.

Homework Statement A problem of practical interest is to make a beam of electrons turn a 90∘ corner. This can be done with the parallel-plate capacitor shown in the figure (Figure 1) . An electron with kinetic energy 2.0×10−17 J enters through a small hole in the bottom plate of the capacitor...

Ah yes, good catch. I wrapped the whole thing in a cube root and the answer is closer to correct but still not there. I'm probably missing something simple but I am just not seeing it. Link EDIT: I got it! I had 8 nC instead of 80. Thank you all!

Hmmm. 4.1 degrees? Can you look at my link here and see what I entered wrong? Thank you all for helping me through this btw!

Yes, here's my link.

Hm, I tried that and it didn't seem to work unfortunately. Why is it that I can make that assumption anyway? EDIT: Just used all my attempts and got that the correct answer is 4.1 degrees. Still need to figure this out since it's for studying.

Homework Statement Two m = 4.0 g point charges on 1.0-m-long threads repel each other after being charged to q = 80 nC , as shown in the figure. What is the angle θ? You can assume that θ is a small angle. Homework Equations Fe=kq2/r2 F=ma Fg=mg The Attempt at a Solution Equation 1:[/B] r =...

Can you help? I worked through this and plugged my numbers in but when I try to solve for theta I don't get any kind of real number. Here's what I put in Wolfram Alpha: http://www.wolframalpha.com/input/?i=(sin(x))%5E2*tan(x)%3D8.99*10%5E9*(8*10%5E-9)%5E2%2F(4*4*10%5E-3*9.8)+for+x+in+degrees...