Coulomb’s Law
By: Jay’ Len Boone
Inverse square Law
The Law states…
“The magnitude of the electrostatic force of interaction between two
point charges is directly proportional to the scalar multiplication of the
magnitudes of charges and inversely proportional to the square of the
distance between them. The force is along the straight line joining them.
If the two charges have the same sign, the electrostatic force between
them is repulsive; if they have different sign, the force between them is
attractive.”
Understanding the Law
•
•
•
-
Interaction between charged object(s)
The charges involved acts over some distance of separation.
Factors of charge:
Sign
Distance
Charges
Positive Charge
Negative Charge
• Protons
• Two Positive charges repel.
• One Proton + One Electron=
Attractive
• Electrons
• Two negative charges repel.
• One Electron + One Proton=
Attractive.
Equation
𝒌𝑸𝟏 ∗ 𝑸𝟐
𝑭=
𝒅𝟐
Understanding Electrical Force Equation
𝑘𝑄1 ∗ 𝑄2
𝐹=
𝑑2
K= 9.0 ∗
109 𝑁𝑚2
𝐶2
Q = Charge
D= Distance
F = Force
How to use the Equation
9.0∗109 𝑁𝑚2
F=
𝐶2
∗
6.25∗10−9 C 6.25∗10−9 C
0.617m 2
109 𝑁𝑚2
𝐶2
K= 9.0 ∗
Q1 & Q2= (6.25 ∗ 10−9 𝐶)
D= 0.617𝑚 2
Using the normal laws of math and PEMDAS I got…
…
𝐹 = 9.23 ∗ 10−7 𝑁
(Newtons)
To Conclude…
Coulomb’s Law has a lot to It but this
PowerPoint should put it in layman’s
terms for those of us who struggle
with this topic. To find out more visit:
http://www.physicsclassroom.com/cla
ss/estatics/Lesson-3/Coulomb-s-Law
Also here is a screenshot of an electric
field hockey simulation I did in class.
As portrayed, the puck is being
repelled down by the positive charges
at the top, but being attracted towards
the goal by the negative charges .
To try the simulation yourself visit:
http://phet.colorado.edu/en/simulatio
n/electric-hockey