PLEASE help... need to be done asap for uni app

[siemieniuk]

Hey all... thanks for looking. I've got three questions that I'm having trouble with... I have some crap done on them, but I'm just plain stuck... can someone help me out with all 3??? I need to be done these like yesterday so I can get my mark to the university. :cry:

I scanned in the questions and attached them. One question is split between the scans (words on one and diagrams on another).

Steve

[Tom Mattson]

These are both problems regarding static equilibrium. That means that you need to sum the forces in the x and y directions, set them equal to zero, and solve for your unknowns.

For the second problem, note that if an electric charge is at the origin, then its field is:

E(x,y)=kq/r2=kq/(x2+y2)1/2

If the charge is not at the origin, but rather is displaced by cx units in the x direction and cy units in the y direction, then the function is shifted, as follows:

E(x,y)=kq/[(x-cx)2+(y-cy)2)]1/2