Show that this equation is inverse square

[brycenrg]

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.

 

[RUber]

This function is dependent on the inverse squared of r, which is usually the distance between the locations of Q1 and Q2.

 

[SammyS]

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.

 

[brycenrg]

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]

Thank you so, r is the only value that is changing?

Yes. That is exactly what "inverse square" means. Google is your friend; see
https://en.wikipedia.org/wiki/Inverse-square_law

 

[brycenrg]

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.