Consider four masses arranged (clockwise from A at the top) in a cross (looks like a giant plus symbol). Each is 1cm from the center of the cross. Mass A has a charge +1𝜇C , mass B has a charge of −1𝜇C , and mass C has a charge of +2𝜇C . At the center the electric field points 30 degrees (Northeast) from the vertical axis.

Question

Is there a formula I need to find the missing value of D? I tried setting opposite ends equal to separate and find D but I cant figure this out or find anything online like it. Thank you.

Answer 1

look at the relative field strengths (at the center) from the individual charges
... they are all one cm away
... so the contribution to the net field is proportional to the charge

north-south is +1 N

east-west is ... D - 1 E

(E-W) / (N-S) = tan(30º)

Answer 2

I calculated a charge of -1.1547E-6

I used the (force between north and south and multiplied that by tan(30) ) and set that equal to (E*W) to solve for W. Is this what you were saying? Sorry I'm new to Physics so I'm trying to get this right to refer back to later on.

Thank you

Answer 3

I immediately realized how my interpretation & calculations were incorrect, but can you help elaborate further on how to solve for the value of the charge on D?

If you have time to write out the steps that would be greatly appreciated, I already lost my chance to earn credit for the problem but would love to know how to solve this.

Thank you.

Answer 4

i need help with this exact same question, could someone please answer?