Recent content by Raul Trejo

Note: I just realized I put -3.20x10^-19C, it's actually 10^-9. We have -3.20x10^-9C . All charge is "quantized" meaning it is an integer multiple of the charge "e" (-1.602x10^-19C/electron). To obtain the amount of "excess" (Neutrally charged atoms have the same amount of protons and electrons...

Homework Statement Excess electrons are placed on a small lead sphere with mass 8.00g so that it's net charge is -3.20x10^-9C (a) Find the number of excess electrons on the sphere. (b) how many excess electrons are there per lead atom? The atomic number of lead is 82, and its atomic mass is...

I did respond them, but the stayed inside the quotation marks. What does dU/dr represent in terms of this velocity profile? It is the rate of change that the velocity experiments as the distance from the centerline changes too. What is its physical significance? It allows us to see the shape...

Yes, I differentiated in respect to r. The problem is that the sear stress equation has an added - sign at the beginning when the original equation doesn't, the differential result is the same for both cases, except for the sign. I just can't picture why du/dr is negative in pipe flow? Isn't...

The velocity is reduced to 0, because the plates are fixed and the no slip condition allows us to assume the velocity the fluid has at R is equal to 0. I read the solution manual again in hopes of understanding the issue. So it says that du/dr=-du/dy because y=R-r, where y would be the distance...

Homework Statement Consider the flow of a fluid with viscosity μ through a circular pipe. The velocity profile in the pipe is given as U(r)=Umax(1-rn/Rn), where Umax is the maximum flow velocity which occurs at the center line; r is the radial distance from the centerline; and U(r) is the flow...