What is the magnitude of the electrostatic force between two point charges?

In summary, The problem involves finding the magnitude of the electrostatic force on a charge Q1 given its distance and the magnitude of another charge Q2. Using Coulomb's Law, the force is calculated to be approximately 1.3*10^10 N. However, the answer keeps coming up as incorrect, possibly due to a bug in the online grading system or a discrepancy in significant figures. Further clarification from a professor may be needed.
  • #1
therealkellys
16
0
I've been working on the following problem but when I try my answer online, it keeps coming up as incorrect. A charge Q1=-9.4 C is 4.8 m from a charge Q2 = 3.6 C. What is the magnitude of the electrostatic force on Q1?

I'm pretty sure for this its just Coulomb's Law so:
F = (k(Q1*Q2))/r^2
F = ((8.9876*10^9)(-9.4*3.6))(4.8^2)
F ~ 1.32 * 10^10 N
Taking into account sig. figs, my final answer is 1.3*10^10 N. \

However, this keeps coming up as incorrect. Am I overlooking something? Thanks in advance for the help!
 
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  • #2
therealkellys said:
I've been working on the following problem but when I try my answer online, it keeps coming up as incorrect. A charge Q1=-9.4 C is 4.8 m from a charge Q2 = 3.6 C. What is the magnitude of the electrostatic force on Q1?

I'm pretty sure for this its just Coulomb's Law so:
F = (k(Q1*Q2))/r^2
F = ((8.9876*10^9)(-9.4*3.6))(4.8^2)
F ~ 1.32 * 10^10 N
Taking into account sig. figs, my final answer is 1.3*10^10 N. \

However, this keeps coming up as incorrect. Am I overlooking something? Thanks in advance for the help!
Sounds right to me. Are you sure that the charges are given in Coulombs (and not microcoulombs or nanocoulombs)? Other than that, I can't see anything wrong.

Patrick
 
  • #3
Yep, I just looked it over again and all charges are given in Coulomb's. I think I might email my professor to see if he can look it over. Perhaps its a bug in the online grading system? I'm fairly confident in my answer. Thanks for looking it over!
 
  • #4
therealkellys said:
Yep, I just looked it over again and all charges are given in Coulomb's. I think I might email my professor to see if he can look it over. Perhaps its a bug in the online grading system? I'm fairly confident in my answer. Thanks for looking it over!
You are welcome. Yes, it might be a big. Or maybe the system is expecting an answer with 3 sig figs (even though the answer should really have only two sig figs). But your answer is correct.

Best luck!

Patrick
 

What is the force between two point charges?

The force between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. It can be calculated using the Coulomb's Law equation: F = (k * q1 * q2) / r^2, where k is the Coulomb's constant, q1 and q2 are the charges, and r is the distance between them.

How do the magnitude and direction of the charges affect the force between them?

The magnitude of the charges directly affects the magnitude of the force between them. The larger the charges, the greater the force. The direction of the charges also plays a role in determining the direction of the force. Like charges repel each other, while opposite charges attract.

What happens to the force between two point charges if the distance between them is increased?

If the distance between two point charges is increased, the force between them decreases. This is because the force is inversely proportional to the square of the distance between them. Therefore, as the distance increases, the force decreases.

Can the force between two point charges be negative?

Yes, the force between two point charges can be negative. This occurs when the charges have opposite signs, resulting in an attractive force. If the charges have the same sign, the force will be positive, indicating a repulsive force.

What is the unit of measurement for the force between two point charges?

The unit of measurement for the force between two point charges is Newtons (N). This is the standard unit for force in the International System of Units (SI).

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