Electrostatics problem (ruddy angles)

[Destrio]

Homework Statement

Calculate the magnitude of the field strength at point P as shown. The distance between the centers of the 1.5E-6 C and the 9.2E-6 C charges is 5.6 cm..

Homework Equations

E = kq/r^2
E = F/Q
E = V/d

The Attempt at a Solution

Used tan and sin of 50 to find all distances

E = kq/r^2
E = (9E9)(1.5E-6C) / (7.31E-2 m)^2
E = 2.526E6 N/C

E = kq/r^2
E = (9E9)(9.2E-6C) / (4.69E-2 m)^2
E = 2.526E6 N/C

then used those numbers to find c^2 using cosine law.

I'm not getting a correct answer (obvoiusly).

Thanks,

 

[Destrio]

picture is now working

 

[berkeman]

What's a c^2 cosine law? You have the two vector components of the total E field. Do you know how to add the components? Is the answer expressed in polar or rectangular form?

 

[Destrio]

cosine law is:
c^2 = a^2 + b^2 - 2ab cos c
I don't know how to add the components or what polar/rectangular form is

 

[OlderDan]

Homework Statement

Calculate the magnitude of the field strength at point P as shown. The distance between the centers of the 1.5E-6 C and the 9.2E-6 C charges is 5.6 cm..

Homework Equations

E = kq/r^2
E = F/Q
E = V/d

The Attempt at a Solution

Used tan and sin of 50 to find all distances

E = kq/r^2
E = (9E9)(1.5E-6C) / (7.31E-2 m)^2
E = 2.526E6 N/C

E = kq/r^2
E = (9E9)(9.2E-6C) / (4.69E-2 m)^2
E = 2.526E6 N/C

then used those numbers to find c^2 using cosine law.

I'm not getting a correct answer (obvoiusly).

Thanks,

There is no way the fields from the two charges are the same. Your distances look OK.