Physics question-finding the magnitude of the electric field

AI Thread Summary
To find the magnitude of the electric field acting on a charged insulating ball, it is essential to consider both the gravitational force and the tension in the thread. The ball, with a mass of 7.0g and a charge of 1.5mC, is inclined at an angle of 8 degrees to the vertical, which affects the force components. The correct approach involves analyzing the forces acting on the ball, including drawing a diagram to separate vertical and horizontal components. The formula e = Fe/q is applicable, but it must be adjusted to account for the tension in the string and the angle of inclination. Understanding the net force and direction of the electric field is crucial for solving the problem accurately.
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Physics question--finding the magnitude of the electric field

Homework Statement


A charged insulating ball of mass 7.0g with a uniform charge of 1.5mC hangs from a light thread inclined at an angle of 8 degrees to the vertical. Calculate the magnitude of the electric field.

Homework Equations


q=mg/e

e= Fe/q

The Attempt at a Solution


I tried to use e=mg/q and i kept getting the wrong answer. I am not sure how or if i should use the given angle.Im confused because i don't know which formula i need to use for this question.
 
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nba23 said:
I tried to use e=mg/q and i kept getting the wrong answer.
That would apply if the ball were suspended solely by the electric field, but its not--there's a string attached.
I am not sure how or if i should use the given angle.Im confused because i don't know which formula i need to use for this question.
Which way does the field point? (I presume horizontally.)

What forces act on the ball? (Draw a diagram for yourself.) What must the net force be? Hint: Consider vertical and horizontal force components separately.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
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