Easy homework problem I know, how original.

In summary, the problem involves finding the resultant force on a positive charge q situated at the center of a square with sides of length a, where four point charges are located at the corners of the square. Using the equation F=Ke(q1q2/m^2) and the given value of the constant Ke, the forces of each negative charge on the positive charge can be calculated. By considering the symmetry of the problem, it can be simplified to adding the three force vectors. The distance between the positive charge and the top right negative charge is 2sqrt(a), which can be simplified to a\sqrt{2}.
  • #1
WardenOfTheMint
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Homework Statement


Four point charges are situated at the corners of a square with sides of length a.
Find the resultant force on the positive charge q. HINT: write an expression for the resultant force, use Ke for Ke, q for q, and a for a! That makes sense, because not much information is given.


HERE is a picture.



Homework Equations



F=Ke ( q1q2 / m^2 )

Ke is the constant 8.99e9 Nm^2/C^2.

Q1 and Q2 are any two charges of interest. That m^2 basically means the distance between two should be charges squared. So if distance between two charges is 5 cm, then it should be (0.05m)^2.

The Attempt at a Solution



F of top left negative charge on positive charge = Ke ( q^2 / a^2 ) ?

F of top right negative charge on positive charge =Ke ( q^2 / ( (2sqrt(a))^2 ) ?

F of bottom right negative charge on positive charge = Ke ( q^2 / a^2 ) ?

I don't know what I'm doing.
I figured that if you make a 45 45 90 triangle out of that square, the length between the positive charge and the top right charge should be 2sqrt(a). Other than that I do not know.
 
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  • #2
That distance should be [tex]\sqrt{a^2+a^2} = a\sqrt{2}[/tex] So the distance square is just 2a^2.

Draw a picture of the 3 force vectors... You need to add the 3 vectors... but the problem can be simplified when you see the symmetry...
 
  • #3


As a scientist, it is important to remember that there are no "easy" homework problems. Every problem, no matter how simple it may seem, has value in helping us understand and apply scientific principles. In this problem, you are being asked to find the resultant force on a positive charge in a system of four point charges. This is a fundamental concept in electromagnetism and has real-world applications in fields such as engineering and physics.

To solve this problem, you can use Coulomb's law, which states that the force between two charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. In this case, you have four charges arranged in a square, so you can calculate the force between each charge and the positive charge using this equation. Then, you can find the resultant force by adding up the individual forces using vector addition.

It is important to carefully consider the information given in a problem and use the correct equations and units. In this case, you correctly identified the constant, Ke, and the charges, q1 and q2. However, the distance between two charges should not be squared in the equation. It should be the square of the distance, which is given by a^2 for a square with sides of length a. Also, be careful with the units. The distance should be in meters, not centimeters.

Overall, it seems like you are on the right track in your solution attempt. Keep in mind the units and equations, and don't be afraid to ask for help or clarification if you are unsure. Remember, even "easy" problems have value in helping us understand and apply scientific principles.
 

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The purpose of assigning easy homework problems is to help students practice and reinforce their understanding of basic concepts. These problems may also serve as a warm-up activity to get students thinking critically and preparing them for more challenging assignments in the future.

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Teachers may assign easy homework problems as a form of review or to assess students' comprehension of the material. It also allows teachers to identify students who may be struggling with the material and provide additional support if needed.

3. Is it okay to skip easy homework problems?

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5. Should I ask for help with easy homework problems?

Yes, it is always okay to ask for help with easy homework problems. Seeking help from your teacher or classmates can provide valuable insights and help you better understand the material. It also shows that you are committed to learning and improving your understanding of the subject.

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