TAsk 4: Finding the force exerted on a charge

A fourth charge of q4= -2 uC is placed at P. Find the magnitude and direction of the force experience by q4. Use formula F = qE.

TAsk 3: Finding resultant E-vector.

x -comp: Er= E3 + E2x
y-comp: Er= E1- E2y
Use pythagoras theorem to find magnitude and tan (angle) = Ey/Ex to find the direction of the resultant E vector.

Given that :
q1= 7 uC
q2= -5 uC
q3= -3 uC
where 1 uC is 1 microcoulomb.

TAsk 2: Knowing the source of E-vector

E1= kq1/(0.4)2
E2= kq2/(0.5)2
E3= kq3/(0.3)2

TAsk 1 : Pointing in the correct direction

Which charge is positive?
Which charge is negative?