Search
Ask a question

Answers by Steven W.

Hi Vans!  It looks like this problems is set up as a Young's double-slit experiment (substituting the two point sources for the slits).  The clue is that the detection point is much, much farther (1000 times farther) from the sources than the sources are from each other.    NOTE: ...

Hi Achillos!   I will assume these problems are numbered 1 - 5, top to bottom.   1.  This problem uses the equilibrium conditions from statics.  Using x-y (Cartesian) coordinates, I usually write these as three conditions:   (a) sum of the x-direction...

Hi Nechama!   If we treat the salmon as a projectile, we can break the problem down into horizontal and vertical motion, and look at the conditions on each.   HORIZONTAL --------------- In the horizontal direction, by definition, there is no acceleration for a projectile...

If this still will help:   The expression for the electric potential at the surface (referenced to 0 at infinity) is pretty straightforward, since the entire spherically symmetric distribution is contained within that position.  Therefore, it presents the same electric potential...

If you still need help with this one, I would suggest setting up Newton's 2nd law in either the horizontal or vertical direction.  I would start with the horizontal, since there are fewer force components at work in that direction (since gravity is not present in the horizontal).  You...

This can be solved using the definition of Young's modulus, as the ratio of applied stress to compressive or tensile strain.  This can be written as:   E = stress/strain = (F/A)/(ΔL/L)   where   F = applied force A = cross-sectional area of the material...

RAY DIAGRAMS... (answer)

Hi Pia!   I think the solution in the video you linked to is incorrect.  There should be a third imaging considered, because the light physically returns through the lens.  The person in the video is treating the system as if it were two lenses, but mirrors and lenses are...

Gauss's Law (answer)

Hi Gustavo!   Gauss' law combined with a symmetry argument can show the electric field at the exact center of a uniform sphere of charge is zero.  The same applies in this case, since the off-axis cavities are placed symmetrically around the center.   It can be shown...

physics help (answer)

Hi Porcia!   You should have a table in whatever textbook or class material you have for something called the "temperature coefficient of resistivity (or resistance)," usually symbolized α.  You can also probably find it online.  That coefficient is usually...

Hi Arun!   A board swinging about its end is what is called a "physical pendulum."  In a simple pendulum, the mass is all concentrated at the end of the support, and the rest of the support is considered to have insignificant mass.  In a physical pendulum, though,...

Hi Arifur!   A singularity is a point with a mass density approaching infinity in the limit.  It occurs when all the mass of an object is gravitationally collapsed (under its own weight) to (in the limit) a single point.  This happens with some supermassive stars (I think...

Hi Ben!   It may be better to ask this as a math question, since you are looking to convert your PDE into an ODE along some characteristic curve that you have to discover.  This is, admittedly, not my area of expertise, but I can see what I can find out with a little research....