Shakas
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Homework Statement
Use Coulomb's law to determine the magnitude and direction of the electric field at points A and B in Fig. 16-57 due to the two positive charges (Q = 8.0 µC) shown. Is your result consistent with Fig. 16-31b?
Figure 16-57
Figure 16-31b
A)Find the magnitude of the electric field at point A and direction.
B)Find the magnitude of the electric field at point B and direction.
Homework Equations
E=kQ/r^2
The Attempt at a Solution
A)
Let the left Q charge be Q1
Let the right Q charge be Q2
I started by finding the distance vector between Q1 and A, which is the same for Q2 and A.
sqrt((0.1^2)+(0.05^2))=.111m
I then found the electrical field between Q1 and A, which is the same for Q2 and A, but in the opposite direction.
E=(9e9)(8e-6)/(.111^2)=5.84e6
I then split the electrical field into x and y components. Used law of sines to find the angle.
sin(90)/(.111)=sin(x)/(.05)
x=26.8 degrees
Splitting into x and y components:
Q1 to A.
5.84e6*sin(27)=2.651e6 up
5.84e6*cos(27)=5.203e6 right
Q2 to A.
5.84e6*sin(27)= up
5.84e6*cos(27)=5.203e6 left
The x-components cancel due to opposite directions and the y-components are combined.
2.651e6 + 2.651e6 = 5.3e6 N/C 90 degrees above the horizontal.
This is apparently the wrong answer and I do not know what I am doing wrong...
B)
I'm not going to attempt B until I get part A right...