Recent content by BitterX

Hey, I'm sure you are all familiar with the experiment where you take a glass of water , put a some seal on it and then turn it upside down. Due to the (atmospheric pressure) - (the air pressure in the glass) exerting a force on the seal upwards greater than the [mg] of the water, the seal...

Thanks. I know the second way,and I did it like that. About the first way, can you recommend on a book that show how to do it? in our course it was only when z=0... edit: nvm googled it... I feel ashamed. Thanks!

Homework Statement calculate the frenet frame for the vector: \vec{r}(t)=(2t cost,2tsint,5t) calculate the acceleration in frenet frame. Homework Equations \hat{T}=\frac{dr}{ds}=\frac{\dot{r}}{|\dot{r}|} \hat{N}=\frac{\frac{dT}{ds}}{|\frac{dT}{ds}|} \hat{B}=\hat{T}\times \hat{N}The Attempt...

Thanks! I guess I'm blind :)

I'm really sorry, but that's exactly my problem. I can't see how can I separate v and m, If I divide by v and m I'm still stuck with \frac{ ub}{mv}dt and \frac{ k}{m}dt how can I integrate \frac{dt}{m} or \frac{dt}{mv}? and more generally, is there a text about how to do...

Ok, so: F= ub - kv m\frac{dv}{dt}= ub - kv m\frac{dv}{dt}=ub-k\frac{dx}{dt} now I'm still stuck m\frac{dv}{v}=(\frac{ub}{v}-k)dt vdt=dx \Rightarrow \frac{dt}{v}=\frac{dx}{v^2} = \frac{dv}{v^2 dt} how can I isolate v to be only with dv? should I use m=M_0 - bt?

Because this is not a 'formal' question I won't use the template. I was wondering, what if I have a rocket (varying mass) with air resistance acting upon it? Let's say the F=-kv u is the speed of the rocket relative to the gas, and the rate of mass/second extracted is b without g it would...

ah, of course... it's with a minus :) on paper I actually did it with a minus. Thanks for pointing it out though!

Homework Statement a body with mass M moves across a plane with friction friction constant: \mu = \lambda x^2 the body starts at x=0 with velocity v0 find at what x the body stops and what was the velocity half way there. Homework Equations v^2=v_0^2+2a\Delta x The Attempt at a Solution...

Let's see if I understand, here's an example: I have: a= -40\pi [ \sin (2\pi t^2 - \frac{\pi}{3}) + 4\pi t^2 \cos (2\pi t^2 - \frac{\pi}{3})] \hat{i} + 40\pi [\cos (2\pi t^2 - \frac{\pi}{3})- t^2 \sin (2\pi t^2 - \frac{\pi}{3})] \hat{j} (I derived it from r= 10 \cos (2\pi t^2 -...

Hey I have an accelerated circular motion problem. I have only the position equation, from which I derived the velocity and acceleration. how can I tell what is the tangential acceleration and what is the radial acceleration? If you could point me towards a source to read about the...

Wow, I don't know how I missed it. I plugged t=0 only in -(mg/b)t (so it was 0) and totally ignored the first part :/ Thank you!

Homework Statement a ball with mass m is thrown up from the ground with a velocity v_0 the force due to Air resistance is: F=-bv (there's also gravity) find the velocity and distance with respect to time The Attempt at a Solution I think I got the velocity...

If you are sending it to some kind of online checking system: a. Check to see if they want it in radians. b. Check if all of the starting conditions are correct. c. Take into consideration that they make mistakes too.

I will assume that the force is F=8\hat{i}-3\hat{j} the dot product between F and delta-r: (8,-3)\cdot (2,1) = 8\cdot 2 + (-3)\cdot 1 = 13 the norm of F: ||F||=\sqrt{8^2 +3^2} norm of delta-r : ||\Delta r|| =\sqrt{1^2+2^2} I got 47.12 degrees but it seems you have used different conditions :/