Recent content by aquance

Uh, thanks, it seems that prof made a mistake.

Homework Statement http://i.imgur.com/1j19V0n.jpg Two masses are suspended from a pulley as on the pic. I have pulleys radius R and moment of inertia I and masses m1 m2. Homework Equations The Attempt at a Solution So 2nd law of motion: N_{1} - m_{1}g=m_{1}a m_{2}g-N_{2}...

Ok, can you explain to me (preferably with some example) when should I use the formula with gradient vs this simpler one? And if here I could use the gradient one, how could I make it work?

Uh, but I have to find potential of this ... system? Not for each of the masses I think, that's why I thought this formula isn't good to use here.

Do you mean minus sign in y? Why? Vectors specify the direction and they are clearly all positive. I only know whe formula with gradient, and that's what I should use here, can you just tell me how to properly calculate it?

If you say you got something different then atleast write your different answer, writing everything takes a lot of time in latex y=\frac{GM}{a^{2}}*(1,0)+\frac{GM}{a^{2}}*(0,1)+\frac{GM}{2a^{2}}*( \frac{1}{\sqrt{2}}, \frac{1}{\sqrt{2}}) What about the potential? What is that "simple" formula?

Well what did you come up with for intensity then?

Homework Statement Here is the pic: http://i.imgur.com/olnuDjL.jpgHomework Equations The Attempt at a Solution So intensity was pretty easy, it came up to be y=\frac{GM}{a^{2}}(1+\frac{1}{2\sqrt{2}},1+\frac{1}{2\sqrt{2}}) Check on if it's correct would be nice aswell. Now for potential I know...

Okay nvm I get it, first one was just multiplied by a ratio of what is generating the gravitational effect for our current position, so \frac{x}{R}, am I right?

yeah but I still don't understand why it's \frac{GM}{x^{2}} in x>R case and \frac{GMx}{R^{3}} in the other one. I have no idea where the x^2 go and r^3 and x came Please just help me understand it, I'll never have physics again in my life after tommorows test.

Homework Statement So in this video: https://www.youtube.com/watch?v=rm3x2X0X_Sc&t=210 Why does g.out and g.in have values as shown on the video? I can not for life of my understand it. Homework Equations The Attempt at a Solution

What about potential energy? Is it the same integrals but with just formula -GmM/r instead of what I used here?

Ah okay I dun goofed, with limits of 0 to pi it's actually (0,2) and so we get (0,\frac{2GmM}{\pi*r^{2}}) Which appears to be correcT?

Isn't it that all forces on x-axis are 0?

Ok, so I take it that you just put the integral into the vector so you have (integral of cos, integral of sin)? If so then the result is vector (1,1) which.. does it make sense? It means that equal force vector is (\frac{2GmM}{\pi*r^2}, \frac{2GmM}{\pi*r^2}) Also please answer question about...