More Physics help?

I have received a lot of help from everyone in all my CALC courses and Physics courses....Needless to say I sincerely appreciate it. I am military stationed overseas and they don't teach or have tutors available to help me in these more advanced classes. Teaching myself is fairly difficutlt so thanks to anyone and everyone who helps...now on to the question.





A thin rod of length l carries a total charge Q distributed uniformly along its length. Determine the electric field along the axis of the rod starting at one end-that is, find E(x) for x%26gt;= to 0.


Is this one just looking for an equation??





An electron with speed v0 = 21.5 x 10^6 m/s is traveling parallel to an electric field (v0 IIE) of magnitude E = 11.4 x 10^3 N/C. (a) How far will it travel before it stops? (b) How much time will elapse before it returns to its starting point?

More Physics help?
The first problem can be solved by supplying an appropriate equation. At any distance from the rod, this gets messy as the field will have X, Y, and Z components. But fortunately that is not what is asked: all we need is E(r) for r near zero. And that will simply be given by the charge density along the rod. Compare this problem with the similar one of the field near a charged sphere and the answer should become apparent.





The second problem is simply the same thing as tossing a ball vertically in a gravitational field. The speeds are too small for special relativity to be an issue, so one can do the indicated multiplication of field and charge to get the force. You will need the value of e/m for the electron by the time you are done with this. Note that the time in part b is twice the time in part a.