Show that this equation is inverse square

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    Inverse Square
AI Thread Summary
The equation F = k(Q2*Q1)/(r^2) represents an inverse square law, where the force F is inversely proportional to the square of the distance r between two charges Q1 and Q2. The constant k remains unchanged while varying r allows for observing the relationship. Users are advised to keep Q1 and Q2 constant and only change r to see how it affects the force. This approach clarifies that as r increases, the force decreases according to the inverse square relationship. Understanding this principle is crucial for grasping the underlying physics of the equation.
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Homework Statement


F = k(Q2*Q1)/(r^2)

Homework Equations

The Attempt at a Solution


I asked my teacher and he said that this is an inverse square law. Didn't say anything else. He also mentioned k is constant.

I assume i can plug in random values and see if there is a pattern... k=1 for all
Set 1, q1 = 2, q2 = 4, r = 5
F1 = 8/25
Set 2, q1 = 1 q2 = 5, r = 4
F2 = 5/16
I plugged in random values but i don't really get it.
What is inverse of what? I see that the r is squared and its below the kq1q2. I'm stuck.

Any advice is appreciated.
 
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This function is dependent on the inverse squared of r, which is usually the distance between the locations of Q1 and Q2.
 
brycenrg said:

Homework Statement


F = k(Q2*Q1)/(r^2)

Homework Equations

The Attempt at a Solution


I asked my teacher and he said that this is an inverse square law. Didn't say anything else. He also mentioned k is constant.

I assume i can plug in random values and see if there is a pattern... k=1 for all
Set 1, q1 = 2, q2 = 4, r = 5
F1 = 8/25
Set 2, q1 = 1 q2 = 5, r = 4
F2 = 5/16
I plugged in random values but i don't really get it.
What is inverse of what? I see that the r is squared and its below the kq1q2. I'm stuck.

Any advice is appreciated.
What RUber said . ...

So, pick values for Q1 and Q2 and stay with those. Then plug-in various values for r.
 
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SammyS said:
What RUber said . ...

So, pick values for Q1 and Q2 and stay with those. Then plug-in various values for r.
Thank you so, r is the only value that is changing?
 
Ray Vickson said:
Yes. That is exactly what "inverse square" means. Google is your friend; see
https://en.wikipedia.org/wiki/Inverse-square_law
Thank you, Yeah i googled it but thought the Q's changed as well. So it didn't make sense. Sometimes i need someone to explain it to me like I am 5.
 
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