Feynman’s Paradox: Two charged balls are attached to a horizontal ring that can rotate about a vertical axis without friction. A solenoid with current I is on the axis. Initially, everything is at rest.
The current in the solenoid is turned off. What is the direction of the induced E when viewed from the top?
Feynman’s Paradox: Two charged balls are attached to a horizontal ring that can rotate about a vertical axis without friction. A solenoid with current I is on the axis. Initially, everything is at rest.
The current in the solenoid is turned off. What happens to the charges?
Does the Feynman device violate Conservation of Angular Momentum?
A function, f(x,t), satisfies this PDE:
∂2f∂x2=1c2∂2f∂t2
Invent two different functions f(x,t) that solve this equation. Try to make one of them "boring" and the other "interesting" in some way.
A function, f(x,t), satisfies this PDE:
∂2f∂x2=1c2∂2f∂t2
Which of the following functions work?
A "right moving" solution to the wave equation is:
f_R(z,t) = A \cos(kz – \omega t + \delta)
Which of these do you prefer for a "left moving" soln?
(Assume k, \omega, \delta are positive quantities)
A "right moving" solution to the wave equation is:
f_R(z,t) = A \cos(kz – \omega t + \delta)
How many of these could be a "left moving" soln?
Two different functions f_1(x,t) and f_2(x,t) are solutions of the wave equation.
\dfrac{\partial^2 f}{\partial x^2} = \dfrac{1}{c^2}\dfrac{\partial^2 f}{\partial t^2}
Is (A f_1 + B f_2 ) also a solution of the wave equation?
Two traveling waves 1 and 2 are described by the equations:
y_1(x,t) = 2 \sin(2x – t) y_2(x,t) = 4 \sin(x – 0.8 t)
All the numbers are in the appropriate SI (mks) units.
Which wave has the higher speed?
Two impulse waves are approaching each other, as shown. Which picture correctly shows the total wave when the two waves are passing through each other?
A solution to the wave equation is: f(z,t) = A \cos(kz – \omega t + \delta)
A solution to the wave equation is: f(z,t) = Re\left[A e^{i(kz – \omega t + \delta)}\right]
A complex solution to the wave equation in 3D is:
\widetilde{f}(\mathbf{r},t) = \widetilde{A}e^{i(\mathbf{k}\cdot\mathbf{r}-\omega t)}