Coulomb’s Law Worksheet
Name:__________________________________
Date:________________
Mod:________________
Directions: Answer the questions below using coulomb’s law. Be sure to use SI units when using the
equation. Show all work and circle your final answer.
1. A charged sphere with an excess charge of +5.5mC is placed 0.15m from another charged
sphere, which carries a charge of -9.1μC.
a. What is the magnitude of the electrical force between the two charged spheres?
b. Is this a repulsive or attractive force?
c. How many excess electrons are on the negative sphere?
d. How many electrons has the positive sphere lost?
2. An electron and a proton are 0.1 mm apart. What is the magnitude of the force? Is the force
repulsive or attractive?
3. Two objects are at rest on a table when they are given a charge. The one object has a charge of
+7.8μC and the other has a charge of -0.54mC. The magnitude of the force between the two
objects is 17.5N. What is the distance between the two objects?
Coulomb’s Law Worksheet
Methacton High School Physics Department
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4. An unknown point charge is placed 15cm away from a +2.3μC point charge. The force between
the two charges is +9.95N. What is the charge of the unknown point charge?
5. Three point charges (𝑞1 , 𝑞2 , 𝑞3 ) lie along the x-axis at 𝑥1 = 0, 𝑥2 = 2.5𝑐𝑚 𝑎𝑛𝑑 𝑥3 = 6.0𝑐𝑚.
Calculate the magnitude and direction of the electric force on each of the three points
when𝑞1 = +6.0𝜇𝐶, 𝑞2 = +2.5𝜇𝐶 𝑎𝑛𝑑 𝑞3 = −3.0𝜇𝐶. Include a small picture of the problem.
Coulomb’s Law Worksheet
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6. A charged object called B has a charge of -4.2x10-5C and is 0.060m north of another charged
object called A that has a charge of +8.4x10-5C. A third charged object called C has a charge of
+2.1x10-5C is 0.140m to the west of object A. Calculate the magnitude and direction of the force
acting on object A. Include a small picture of the problem.
Coulomb’s Law Worksheet
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