Homework Statement
Show that the cardioid r=a(1+cos(theta)) can be represented by r=2acos2(theta/2), 0<=theta<=2pi (theta is between 0 and 2pi).
Homework Equations
The Attempt at a Solution
I'm pretty sure I have to equate the two expressions, but I haven't been able to do this...
Oh I see...that makes sense. You're right, I was counting each interaction twice. I worked on the problem again and got (4+sqrt(2))kQ2/a...can anyone confirm this?
Homework Statement
A square of side a has a charge +Q at each corner. What is the electric potential energy of this system of charges?
Express your answer in terms of the variables a, Q and appropriate constants.
Homework Equations
U=kq1q2/r
The Attempt at a Solution
I figured...
I don't quite understand what I've done wrong. I did the calculation again and I'm still getting 7.0x10^-9 C. I'm assuming the units of C are correct since the division yields Joules/Volt, and Joule = Coulomb * Volt. I also checked over my conversion of MV to V and that is correct as well.
Homework Statement
In proton-beam therapy, a high-energy beam of protons is fired at a tumor. The protons come to rest in the tumor, depositing their kinetic energy and breaking apart the tumor’s DNA, thus killing its cells. For one patient, it is desired that 0.10 J of proton energy be...
So does this mean that the way I have set it up is correct? I had a feeling it wasn't right because I couldn't see what steps I'd take next in the event that I had to solve it.
Homework Statement
Set up, but do not evaluate, an integral for the area of the surface obtained by rotating the curve y=xe-x 1=<x=<3 about the y-axis.
Homework Equations
S=integral from a to b x 2pix ds where ds=sqrt(1+(dy/dx)2)dx
The Attempt at a Solution
The first thing I...
I see. So now I'm trying to solve for the distance...I tried doing this by first solving for the path difference by using L1-L2=(n+1/2)lambda, since we know n=2 and lambda=0.5. When I did this, I got the path difference as 1.25. I am now trying to solve for L2 (the distance from the speaker you...