Net Force & Direction Calculation - Homework Solution

[insanitey1]

Homework Statement

Given the screen shots I am to calculate net force, Fc and direction, on the red object after 1.00 s

Homework Equations

The Attempt at a Solution

after doing using basic distance formula to calculate r I got a Force for the blue and red at 4.69x10^-3N and Force of the green and red at 9.04X10^-3N. I think i need to calculate Theta next but I am not sure any help is much appreciated.

 

[EWH]

I would think you need a vector equation for force with time as the dependent variable. Is the second picture a given or is it your work? From the initial picture, all three charges should move (else why specify all three masses?), but the second picture only shows one charge moving.

If the 2nd pic is a given, then I'd figure the x and y distances for each, apply the inverse square law to each and add up the x and y forces separately, then combine the components using a rectangular to polar conversion to get an angle and a force.

Perhaps working in center of mass coordinates might be easier if all charges are actually moving away from each other rather than having 2 fixed.

 

[insanitey1]

Yes the second one is a given. I was going to use basic trig and find the angle and that F+F and incorporate the angle does this sound right?