Net Electrostatic Force on a neg charge next to a pos charge inbetween a field

Therefore, the force on Q1 from the plates is to the left, and the force on Q1 from Q2 is to the right. The net force on Q1 is the sum of these two forces, resulting in a net force of 0.0238 N to the right.
  • #1
hopeless123
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Homework Statement


Two point charges, Q1 = -6.9 µC and Q2 = 1.1 µC are located between two oppositely charged parallel plates, as shown in Fig. 16-65. The two charges are separated by a distance of x = 0.38 m. Assume that the electric field produced by the charged plates is uniform and equal to E = 72000 N/C. Calculate the net electrostatic force on Q1 and give its direction.
16_49.gif


Homework Equations


Felectric = K (Q1 * Q2) / (r^2)

Felectric = qE

The Attempt at a Solution


I'm unsure how to approach from this point. I found the force between the two charges.

F = (9x10^9) [(6.9 x 10^-6)(1.1 x 10^-6) / (.38 ^2)] = .4730609418 N

Then i figured that because it is a constant electric field I could use this equation.
Since the problem states it wants the net charge on Q1, i used that charge for this equation.
F = qE = (6.9 x 10^-6)(72000) = .4968 N

Now I'm trying to find the netforce and whatever I put in seems to be wrong. Electric fields flow from positive to negative so I figured adding these two values would be the correct answer. The force of attraction to Q2 to the right and the force of the electric field to the right. What am I doing wrong?
 
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  • #2
Two forces are acting on Q1. The electric field produced by the plates and the electric field produced by Q2. Consider the signs of the charges. Q1 is negative therefore the direction of the force on Q1 from the plates is to the left and the magnitude of this force is F=QE. The direction of the force on Q1 from Q2 is to the right and it's magnitude is F=KQ1Q2/x2. The force directions are both horizontal so the net force on Q1 can be easily found. I'm assuming the charges are fixed.
 
  • #3
In the electric field, the negative charge moves in the opposite direction of the electric field.
 

1. What is net electrostatic force?

Net electrostatic force is the overall force exerted on a charged particle in an electric field. It is a vector quantity and is determined by the electric field strength and the magnitude and direction of the charge.

2. How is net electrostatic force calculated?

The net electrostatic force can be calculated using Coulomb's Law, which states that the force between two charged particles is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. This can be represented mathematically as F = k(q1q2)/r^2, where F is the force, k is a constant, q1 and q2 are the charges, and r is the distance between them.

3. What is the direction of net electrostatic force?

The direction of the net electrostatic force depends on the relative positions of the positive and negative charges. If the charges are the same, the force will be repulsive and if the charges are opposite, the force will be attractive. The direction of the force is also determined by the direction of the electric field, which is from positive to negative.

4. How does the presence of a positive charge affect the net electrostatic force on a negative charge?

The presence of a positive charge next to a negative charge will result in an attractive force between the two charges. This is because the positive charge will create an electric field that points towards it, and the negative charge will experience a force in the direction of this field. Therefore, the net electrostatic force on the negative charge will be in the direction of the positive charge.

5. How does the distance between the positive and negative charges affect the net electrostatic force?

The net electrostatic force is inversely proportional to the square of the distance between the charges. This means that as the distance between the charges increases, the force decreases. This is because the electric field weakens as the distance increases, resulting in a weaker force between the charges.

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