Recent content by JolleJ

Thanks. Yes, that is a good idea. However, the expression is so complicated that it doesn't really help. I can't show the expressions are the same. And actually, which I should have clarified, I do need the simplified expression.

After doing A LOT of simplification on a complicated expression I am now at a point where my own skills can't take me any further. My problem is that I have an expression, which I am almost certain must be real, but it contains the imaginary units here and there. I have tried using Maple and...

Thank you very much JCVD ! What a great way to do it.

Yes, but I am not having an easier time calculating this. Knowing this would obviously solve my problem; but this is an even harder question. Harder in the sense that my need (l = 0) is a subproblem.

I been thinking sort of down the roads of what you're doing... @Kai: Your suggestion gives negative results for m=100, k=50...

You have k urns and M (M>k) balls. Each ball is placed in a random urn (w/ uniform distrubution). What is the probability that every urn has at least one ball in it after the M balls are placed?

No ideas? :(

The time to make the jump: Solve for t in: h = ½*g*t^2. And then solve for v0 in: s = v0*t. For the direction, just make the two values an vector, and determine the angle.

1. Correct. 2. Corerct, because they can have different masse: F = m*a. 3. Not neccesarily, it could change the direction instead (but he may be meaning that it is the velocity vector, in which case it would be true). 4. True. Newtons third law says the both forces will be equal in size. Action...

Homework Statement You have to find the value of k in the drag equation; Fdrag = k*v^2 It is for a car driving. The motors maximal effect is P = 60W, and it uses this, when the car drives 120 km/h or above. Previously, I have calculated that between 30 km/h and 120 km/h, the resulting...

Haha. :)

It works now, so there's no problem. :) Thanks though. :D

Thank you very much, all of you, however I just got respons from my teacher, who said there was an error in the question. It should be T = 0,835 s. And now everything works. Thanks again !

Thank you both very much! However, I'm still having one problem. What is the period of the movement? I've heard that it's larger than for an undamped pendulum. Is this true? And also, is the period constant for a damped pendulum? I can't tell this from the equations, but some of you can maybe...

Thank you. However I can't quite follow you. I've never seen cylindrical coordinates before. I'm trying to get to this: -D\theta - br\dot{\theta} = I\ddot{\theta} Simply don't know how to explain it in my text. I know you just did it, but can't it be done using normal coordiantes (so that I can...