Recent content by MrLiou168

Thanks Doc. So in this case would I simply integrate to find W? As in W = integral (F*dx) and then W = integral(kxdx) = (kd^2)/2 ...?

Homework Statement A spring with stiffness k and unstretched length L is stretched so the elongation is d = x2 - L. A force is applied to make the final length of the spring x2. What is the work done by the force in terms of d? Homework Equations W = F * d = F*dx d = x2 - L F = k*dx...

Tim, thank you very much - you were extremely helpful!

A ha thank you for your patience! OK so one of the givens is that [sum] Fi = 0... Therefore the right side of the equation nets zero and we have proven that T-T' = 0 and thus T = T' correct?

Oh... sorry I didn't realize the F's were summed as well... So I have (x0 - x0') X Fi = 0? And since Fi is not zero, the x0 = x0'...?

Thanks for the reply! But not quite, I'm a bit of a dim light most of the time... So assuming T = T', then T-T' = 0... And subtracting the 2 equations nets me x0 - x0'. Therefore, is it sufficient to simply state that x0 - x0' = 0 to prove that the resultant torque is independent of choice...

Homework Statement Let a system of forces (F1,...Fn) act on a body at points (x1,...xn) respectively. Assume that the resultant or net force vanishes (sum of forces = 0) Show that the resultant torque of this system is independent of the choice of origin, i.e. for 2 different origins x0...

Thanks for your help, much appreciated. As a side note, for those of you attempting this problem, Mastering Physics does not recognize the answer if you enter 270 degrees. Use NEGATIVE 90 degrees.

OK I think I'm beginning to get it... since capacitance dominates, it won't cancel the effect of the inductance, but the circuit will "look" like a capacitor, so voltage will lag current by pi/2...?

Thanks, but I still don't understand. There is no mention of imaginary numbers in my textbook, and no equation that involves angles other than the ones I listed initially. Should I simply consider reactance = resistance = R = 566.6 ohms and use it in my 2rd equation above?

I calculated X_L = 100 and X_C = 667 and I guess the signed sum is >0. And since the capacitive reactance is larger, I assume that capacitance dominates the circuit. How does this lead to obtaining a value for R in order to get the phase angle?

Homework Statement You have a 0.400H inductor and a 6 micro-Farad capacitor. Suppose you take the inductor and capacitor and make a series circuit with a voltage source that has a voltage amplitude of 30.0V and an angular frequency of 250 rad/s. What is the phase angle (phi) of the source...

Thanks for the response. Those examples are all of coils, and not solid conductors. Does this make a difference? And in terms of the directions of the Eddy currents, is it correct to use I X B = F?

Homework Statement I'm trying to figure out and explanation as to why a strong magnet drops so slowly through a non-magnetic but conducting Cu tube. The attached diagram shows the original B field, induced Eddy currents, and secondary B field as a result of those Eddy currents, but I can't...