Instantaneous response of damped simple harmonic motion
Hi I am trying to model SHM in Simulink as shown here: http://pundit.pratt.duke.edu/wiki/Si...torials/DiffEq I have tried using different values of spring constant and damping to get instant response...
View Articledoes focusing light with a lens create a light gradient?
*disclaimer I am not a physicist Had a weird thought the other day - when you focus light with a lens, for example a magnifying glass, you basically increase the 'concentration of photons' at a certain...
View ArticleB versus H field (and Magnetization)
Hi all, Recently I learned about magnetization I understand that you apply a magnetic field B, and that your magnetization M is proportional to the field ... H? Like so, \mathbf{M}=\chi\mathbf{H} What...
View ArticleEnthalpy of water at triple point and freezing point
By definition we have h=u+pv for a system where h=specific enthalpy u=specific internal energy p=external pressure applied on the system v=specific volume of the system The internal energy is...
View Articlefinding the magnetic field at center of a square loop
My textbook says that at the center of a square conducting wire of length ω, the magnetic field is: B=[itex]\sqrt{2}[/itex]μ[itex]_{0}[/itex]I/([itex]\pi[/itex]R) I am not sure how to calculate...
View ArticleLaw of expansion for super heated steam
Why is super heated steam said to exhibit ideal gas behavior?
View ArticleConfusion with free electrons in metals
Hi, I'm really confused with how electrons become 'free' in a metal. I have a few questions and would be very grateful if someone could shed some light on them. 1. Are the electrons actually free? In a...
View ArticleLockheed Martin F-35 Lightning II engine power?
How can I calculate the power of the engine? Specification: Spec in Wikipedia Dry thrust: 125 kN
View ArticleCalculate number microstates? Why not include acceleration?
I want to calculate the number of microstates in a system for, say, n indistinguishable particles in a 3D box. Some examples I see just represent one microstate as a list of positions. Other examples...
View ArticleMozzi-Chasles Theorem
Hello Forum, I have recently learned about this important theorem of kinematics, the Mozzi-Chasles theorem. I would like to discuss it with the forum if ok. Rotation is a subtle concept and there are a...
View Articlenavier-stokes flow around a sphere
hi pf! basically, i am wondering how to find the velocity profile of slow flow around a sphere in terms of a stream function ##\psi = f(r,\theta)## where we are in spherical coordinates and ##\theta##...
View ArticleAttenuation numerical instability via numerical diss. nonlinear ODE
Hi, I'm solving a problem numerically that takes the form [itex] Q_{ij} \ddot{y}_j +S_{ijk}\dot{y}_j\dot{y}_k +V_i=0[/itex], where [itex] (Q_{ij},S_{ijk},V_i) [/itex] are all functions of the dependent...
View ArticleConfused about conservation of energy
Why is it that when you drop something on a spring, that item dropped on the spring does not bounce back up to where you dropped it from?
View ArticleWhy does the Van der Graaf Generator produce a spark?
Where the electrons come from? Do they leave the sphere or the object? Or maybe even the rubber band inside the generator? I'm having a hard time figuring this out. Also, how does this prove the charge...
View ArticleWhy do TEM modes need two conductors to propagate?
Why do we need two conducting surfaces to allow TEM modes to propagate through a waveguide? Why can we not propagate TEM waves through a single conducting waveguide?
View ArticleWouldn't there be a magnetic force?
Our professor proposed a scenario during lecture that went like this, There is a wire of infinite length that has a current. At a short distance from the wire is a single charge which is stationary...
View ArticleCalculate shadow path & size + object size based on distance
What are the variables I need to take in account if I want to calculate shadow path and size? I will try to simplify my questions. I have a 2d circle (radius: 28) which means the size of the circle (in...
View ArticleBlack body
Hello I am wondering, does a black body release energy as heat, or does it only absorb all energy that basically comes into contact with it? Thanks
View ArticleKnow acceleration as a function of position, can I find velocity?
Hello I know acceleration of a pendulum as a function of angle. Can I find velocity by integration with respect to theta? My intuition says yes, but dimensional analysis tells me otherwise. What is...
View ArticleWhen to use P=I^2R, P=VI, P=V^2/R??
Hi, I know that P = I^2R is to find heat loss. but can we use P = V^2/R or P = IV to find the heat loss? simply when do we use which?? (or can we use all anytime?) The question said to find 1) the...
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