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Show that this equation is inverse square

  • Thread starter brycenrg
  • Start date
  • #1
95
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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.
 

Answers and Replies

  • #2
RUber
Homework Helper
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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.
 
  • #3
SammyS
Staff Emeritus
Science Advisor
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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.
What RUber said . ...

So, pick values for Q1 and Q2 and stay with those. Then plug-in various values for r.
 
  • #4
95
2
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?
 
  • #5
Ray Vickson
Science Advisor
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  • #6
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