Recent content by TheDoctor46

I have been thinking at this for a couple of days now: why are stars grouped in the massive collections that we call galaxies? I can assume that in the very early Universe, matter was grouped in these areas, that matter interacted thus resulting in the formation of stars. Then, the...

Suppose you are given a first order system whose transfer function is HP(s) = KP/(TP*s + 1). Now, you want to control this system using a standard P (proportional) controller whose transfer function is HR(s) = KR (a proportionality coefficient). There is also disturbance that acts upon this...

The thing is that x1+x2 is not a solution for the differential equation, because the two motions do not have the same pulsation(angular velocity).

The idea is to find the resultant motion of these two harmonic motions.

Homework Statement I have 2 simple harmonic motions and I want to compose them on the same axis. So: x1 = A1*sin(ω1*t+θ1) x2 = A2*sin(ω2*t+θ2) The goal is to find the resultant motion of these 2 in the form: X = A*sin(ω*t+Θ), so to find A,ω and Θ as functions of A1,A2,ω1,ω2,θ1 and...

I tried writing 1/3 as the result of an integral from 4 to 7, or 1, but wirh no results. I also tried breaking the fraction, but also, it led nowhere.

So could you please help me demonstrate some inequalities? Please! They want to prove them without calculating the integral. 1/3<=integral from 4 to 7 (x−3)/(x+5)dx<=1Thanks!

Yes, I know that, but I am not able to calculate the equivalent resistance of the highlighted part. I know that the angles in the diagram don't matter, but I can't tell how the resistors are arranged.

I highlighted the part that I am interested in finding. Thanks!

I am able to calculate the parallel resistors, but I can't remember how to proceed for the last group. Thanks!

Hello guys! It's been a while since I last had to deal with direct current and I'm having a hard time solving the equivalent resistance for a simple circuit. I know this is rather simple, but I can't find my notes, so, could you please help me? The photo of the circuit is attached...

https://www.youtube.com/watch?v=m_7vcuzzM5Q&feature=youtube_gdata_player This is, more or less, what I was talking about. Probably my way of explaining the problem in English wasn't the best. Thanks!

Ok. Clearly I wasn't very specific. The problem states that you have an object moving inside a sphere and requires that you find the reaction force from the surface at a specific angle from the from the center, knowing the mass of the object and its velocity. Hope that's better! Thanks!

Hello! I need to find the force exerted by a sphere on an object, with the height of the object on the sphere and the object of the mass konwn. I need to find the reaction of the spherical surface on the object. Thanks!