Repeat Exercise 21.17 for q3 = +8.00 .

Name: Problem 18, Chapter 21: University Physics with Modern Physics
Uploaded: 2019-08-14T10:31:35-08:00
Duration: 5 min 17 s
Channel: Ze-Han Lee
Description: Repeat Exercise 21.17 for q3 = +8.00 .

Key Concepts

Electrostatic Equilibrium

Electrostatic equilibrium refers to the condition in which a charge experiences a net force of zero, meaning that all individual forces acting on the charge balance out. This concept is important for determining positions or configurations in multi-charge systems where the resulting forces cancel each other, often a key goal in many electrostatics problems.

Superposition Principle

The superposition principle in electrostatics asserts that the net force or field experienced by a charge due to a collection of other charges is the vector sum of the forces or fields produced by each individual charge independently. This concept is crucial for analyzing systems with multiple charges, as it allows for the individual contributions to be summed to find the overall effect.

Coulomb's Law

Coulomb's Law quantifies the electrostatic force between two point charges. It states that the magnitude of the force is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them, providing a mathematical framework for calculating interactions in systems of charges.

Electric Charge

Electric charge is a fundamental property of matter that determines how particles interact via the electromagnetic force. It comes in positive and negative forms, with like charges repelling and unlike charges attracting, forming the basis for understanding force interactions in electrostatics.

Transcript

00:02 Alright, in this problem, so we have three charges.

00:10 Q1, so this is origin and q1 is located here with charge 3 microculums.

00:18 And this is x equal 0 .2 meters and q2 is located here with charge negative 5 microcrums.

00:28 And we also know there is another one, q3.

00:32 Equal 8 microponons, but we do not know the location.

00:38 So the question is if we have known the force acting on q3, so f3 equal negative 8 newtons, sorry, negative 7, 7 neutins, which means the magnitude of the force is 7 and the direction is pointing to the left.

01:00 So we want to find out the location of q3.

01:03 So basically, as you can see that there are three regions separated by the two charges q1 and q2.

01:12 So region 1, 2, and 3.

01:16 So let's check the region 1.

01:20 If the q3 is over here, so we know that q3 is positive, so q1 is positive, q2 is negative, then the force induced by q1 is pointing to the left, the force induced by q2 is pointing to the right.

01:35 So it is possible that we have a force which is pointing to the left.

01:39 So region 1 is okay.

01:41 And the region 2, if the q3 is over here, we see that the force induced by q1 is pointing to the right.

01:51 And the force induced by q2 is also pointing to the right.

01:55 So the combined force is definitely pointing to the right.

01:58 So that's not what we want.

02:02 And for the region 3, if q3 is over here, the force induced by q1 is pointing to the right, and the force induced by q2 is pointing to the left.

02:15 So it is also possible that we have a, we have a, we can place the q3 here.

02:23 So it is also possible.

02:25 So the only two possible regions are region one, the region three.

02:31 In region one, the force, i mean the combined force acting on q3, can have the expression f3 equal negative 1 over 4 pi epsilon times q1 q3 divide by r squared and the plus q2 q3 divided by r minus 0 .2 squared yeah so this is the force induced by q1 q3, induced by q1.

03:09 So this is force induced by q2.

03:13 And r is the coordinate of q3...

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