Recent content by NiendorfPhysics

Nevermind I got it thank you for the help

So $$U_{total} = \frac{1}{2} C (ln(\frac{b}{a}))^2$$ and $$U_{radial} = \frac{1}{2} C (ln(\frac{R}{a}))^2$$? I know this is wrong but I don't know what is right.

Homework Statement There is a solid cylinder of radius a and then empty space then a shell cylinder of radius b. Show that half of the stored potential energy lies within a cylinder of radius $$\sqrt{ab}$$ Homework Equations In the attempt The Attempt at a Solution I'm not sure what they...

Wow, I'm stupid. Thanks.

I multiplied the charge density by the volume of the sphere that you have if you are at some point r between a and b. So you have to subtract the empty space between the point charge and when the cloud of charge begins at radius a. I cleaned it up a bit so that it is a little more clear.

Fixed it.

Homework Statement The Spherical region a<r<b carries a charge per unit volume of $$\frac{A}{r}$$, where A is constant. At the center there is a point charge q. Find A such that the Electric field in a<r<b is constant. Homework Equations Law of superposition and $$E=\frac{kq}{r^2}$$ The...

4. A boat travels at constant velocity ⃗vo when the motor is on. At t = 0 the motor is turned off and the acceleration of the boat due to the resistive force of the water is ⃗a = −kv^(−1/2⃗)v (with k > 0 a constant). a) Find ⃗a(t), ⃗v(t) and ⃗r(t). b) Find the time and the distance to stop. Or...

The equation was just given to me in that form within the question. Also it says k is a constant >0. Umm as for other context I'm not really sure what else I could say. It asks me to solve for a(t) v(t) and r(t) (all with the vector arrow) and to find the time and distance to stop, but those two...

The first one. Sorry, I have no clue how to format equations on a computer

Homework Statement Don't ruin the problem for me please, I just want to know why there is a velocity vector at the end of this formula. It's really strange since there is velocity in the equation already, so what would the velocity with the vector arrow on top mean? Problem: A boat travels at...