HELP columbs law/charges 2 charges on a line, looking for

In summary, the net electric field at x=0 cm is directed towards the negative charge with a magnitude of 19.1 N/C. At x=5.9 cm, the net electric field is directed towards the negative charge with a magnitude of 4.52 N/C.
  • #1
BATBLady
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Homework Statement


Two charges are placed on the x axis. One of the charges (q1 = +7.7 µC) is at x1 = +2.9 cm and the other (q2 = -22 µC) is at x2 = +9.2 cm.
(a) Find the net electric field (magnitude and direction) at x = 0 cm. (Use the sign of your answer to indicate the direction along the x-axis.)
(b) Find the net electric field (magnitude and direction) at x = +5.9 cm. (Use the sign of your answer to indicate the direction along the x-axis.)


Homework Equations



Columbs law, F=K*(|q1|*|q2|)/r2

The Attempt at a Solution



I'm fairly lost as to how to start this. I know that to figure out the force of the two charges acting on one another you would use the equation above with r being the distance between the two charges. What I don't know is how to figure out the charge on a spot where there is no charge previously. I think that it would be only the positive charge acting on the spot since (field wise) it is the only one that actually goes anywhere near the point. Or am I totally off? Help?
 
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  • #2
The formula for electric field is
E = k*q/r^2.
The direction of field depends on the sign of the charge. It is away from the positive charge and towards the negative charge.
 
  • #3


Hello, thank you for reaching out for help with your homework problem. I can provide some guidance on how to approach this problem using the principles of Coulomb's law and electric fields.

First, let's define the variables given in the problem. q1 and q2 are the two charges placed on the x-axis, and x1 and x2 are their corresponding positions. To find the net electric field at a given point, we need to consider the contributions of both charges to that point.

To start, we can use Coulomb's law to calculate the electric force between the two charges. The formula you provided is correct, but let's also include the constant K, which is the Coulomb's constant and has a value of 8.99 x 10^9 Nm^2/C^2.

F = K * (|q1|*|q2|)/r^2

Next, we need to consider the direction of the electric field. Electric fields point in the direction of the force that a positive charge would experience if placed in that field. So, for a positive charge, the electric field points away from positive charges and towards negative charges.

(a) To find the net electric field at x = 0 cm, we can calculate the electric force between q1 and q2, and then divide by the distance between them (r = 6.3 cm). Since q1 is positive and q2 is negative, the force between them will be attractive and thus points towards q2. This means that the net electric field at x = 0 cm will also point towards q2, with a magnitude based on the calculated force.

(b) For x = +5.9 cm, we can use the same approach, but now we need to consider the distance between each charge and the point. The force between q1 and the point will be attractive and point towards q1, while the force between q2 and the point will be repulsive and point away from q2. The net electric field will be the vector sum of these two forces.

I hope this helps you understand how to approach this problem. Remember to always consider the direction of the electric field and the sign of the charges when calculating the net electric field at a given point. Good luck with your homework!
 

1. What is Coulomb's Law?

Coulomb's Law is a fundamental law of physics that describes the electrostatic interaction between two charged particles. It states that the force between two point charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.

2. How does Coulomb's Law apply to charges on a line?

When two charges are placed on a line, the distance between them is measured along the line. Coulomb's Law still applies in this scenario, but the distance between the charges must be adjusted accordingly when calculating the force between them.

3. Can Coulomb's Law be used to calculate the force between more than two charges on a line?

Yes, Coulomb's Law can be extended to calculate the force between multiple charges on a line. The total force on a specific charge would be the vector sum of the individual forces from each of the other charges.

4. What are the units of measurement used in Coulomb's Law?

The units used in Coulomb's Law depend on the system of units being used. In SI units, the force is measured in Newtons (N), the charge in Coulombs (C), and the distance in meters (m). In cgs units, the force is measured in dynes (dyn), the charge in statcoulombs (statC), and the distance in centimeters (cm).

5. What are some real-world applications of Coulomb's Law?

Coulomb's Law has numerous applications in everyday life, including the operation of electronic devices, the functioning of batteries, and the behavior of lightning. It is also essential in understanding the structure of atoms and molecules, as well as the behavior of electric fields and charges in various systems.

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