Uniform line of charge and point charge

AI Thread Summary
An infinite line charge with a linear charge density of -3.1 µC/m is located at x = -1 m, while a point charge of 0.7 µC is positioned at x = 2.5 m, y = 3.5 m. The electric field components at the point (3.5 m, 3.0 m) are calculated using Gaussian surfaces for the line charge and Coulomb's law for the point charge. The x-component of the electric field is influenced by both charges, while the y-component primarily derives from the point charge due to cancellation effects from the line charge. The final calculated values for the electric field components are approximately -9545.026 kN/C in the x-direction and -4164.957 kN/C in the y-direction. The discussion highlights a common mistake in trigonometric calculations involving radians versus degrees.
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Homework Statement


An infinite line charge of uniform linear charge density lambda = -3.1 mu or micro CC/m lies parallel to the y-axis at x = -1 m. A point charge of 0.7 mu or micro CC is located at x = 2.5 m, y = 3.5 m. Find the x- and y-components of the electric field at x = 3.5 m, y = 3.0 m.

Homework Equations


flux = E*A = Q/ε
E = kQ/r^2

The Attempt at a Solution


X axis:
To find the electric field from the line only: gaussian cylinder, centered on the line and r = 4.5m.
E*2∏*4.5*L = λL/ε -> E1 = λ/(ε*9*∏) to the left

From the point:
E2 = K(.7*10^-6)/1.25*sin(63.43°) to the right

Ex = E2-E1 Right?

Y axis:
The line don't matter because it cancels itself out. right?
Ey = K(.7*10^-6)/1.25*cos(63.43°) Down

Both answers need to be in kN/C, I'm at a loss, do you guys have any ideas? I have tried many different answers and I've checked all of the units.
 
Last edited:
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Your work looks good to me. What did you get for your final answer?
 
What are your numerical results?

ehild
 
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Welp, I just found my mistake. Damn Radians!
 
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