Recent content by lua

Oh! I did't think of that at all. Thank you!

I'm solving problem number 5 from https://ocw.mit.edu/courses/8-05-quantum-physics-ii-fall-2013/resources/mit8_05f13_ps2/. (a) Here I got: $$ \beta = \frac{\hbar^{\frac{1}{3}}}{(\alpha m)^\frac{1}{6}} $$ and: $$ E = \left ( \frac{\alpha \hbar^4}{m^2} \right )^\frac{1}{3}e $$ (b) Using Scilab I...

Are we talking only about the case (c) or any case listed above? I think I understand what you are trying to say, but I don't understand why system has to start sliding. I understand that when system is rolling, if the resulting velocity of the point of contact with the ground isn't zero...

I think I understand the source of my confusion. I assumed that the condition ##F_{f} \le \mu N## was closely related with the (c) case. But it is not the case. I first considered the case of system dynamics in the middle of the movie. I found parameters of system dynamics (translational and...

I got: $$F_{max}= \frac{1}{2} \frac{sin 2 \alpha}{cos(\alpha - \phi)}mg$$

If you pull harder, I assume that either string will brake or the spool will start to move with constant speed because of zero acceleratios. But I can't prove that. When I look once more through equations, ##F_{max}=T_{max}= \frac{\mu}{cos \phi + \mu sin \phi} mg## is maximum straining force of...

First, for the case (c), I would say that the zero values of translational and rotational acceleration mean one of the following three things: 1. If the spool was accelerating (to the left or right) before meeting requirement (c), it will keep moving with constant linear and rotational speed...

I forgot the figure...

I solved this problem using second Newton law for translational motion and the same law for rotational motion, and got $$a= \frac {F} {m+ \frac {I} {R^{2}}} (cosϕ−rR)$$ where m is spool mass. Now, we have three cases: (a) ##cos\phi>\frac{r}{R}##, when spool is accelerating to the right, (b)...

Hi everyone! I'm a physics anthusiast. I fell in love with physics as soon as I got it in the middle school. Love to read books of the famous physicists (Feynman, Susskind, B. Greene, Penrose, etc.). If my English is sometimes clumsy, I hope you won't mind me - English is not my native...