# Worksheet: Coulomb's Law

In this worksheet, we will practice calculating the forces that electrically charged objects exert on each other, including the net force from multiple charges.

Q1:

An object with a charge of 1.20 C is located 4.50 m away from a second object that has a charge of 0.360 C. Find the electrical force that the objects exert on each other. Use N⋅m2/C2 for the value of Coulomb’s constant. Answer to three significant figures.

• A N
• B N
• C N
• D N
• E N

Q2:

Coulomb’s law defines the electrical force, , that two positively charged objects with the charges and exert on each other. The law relates the force exerted to the distance, , between the objects and to Coulomb’s constant . Which of the following formulas correctly states Coulomb’s law?

• A
• B
• C
• D

Q3:

An object with a charge of 1.50 C and a second charged object that is 0.125 m away exert a force of N on each other. Find the charge on the second charged object. Use N⋅m2/C2 for the value of Coulomb’s constant. Answer to three significant figures.

Q4:

Two positively charged spheres are separated by a distance of 8.5 mm, as shown in the diagram. One sphere has a 20 mC charge and the other has a 10 mC charge. The sphere with the 10 mC charge has a force exerted on it. Find . Use N⋅m2/C for the value of Coulomb’s constant. Give your answer to two significant figures.

• A N
• B N
• C N
• D N
• E N

Q5:

An object with a charge attracts two other objects that have the charges and , as shown in the diagram. The force that exerts on is twice the force that exerts on . The distance from to is 752 µm and the distance from to is 342 μm. If , find . Give your answer to two significant figures.

Q6:

An object with a charge of mC is positioned 8.8 cm directly below an object with a charge of mC, as shown in the diagram. On either side of the negatively charged object, at a distance of 6.3 cm, are objects with the charges mC. Find the magnitude of the net electrical force acting on the negatively charged object. Use N⋅m2/C2 for the value of Coulomb’s constant. Give your answer to two significant figures.

• A N
• B N
• C N
• D N
• E N

Q7:

An object with a negative charge is positioned between two fixed, positively charged objects with the charges C and C, as shown in the diagram. Once positioned, the negatively charged object remains at rest. The distance between the negatively charged object and the object closer to it is 2.5 cm. Find . Give your answer to two significant figures.

Q8:

An object with a charge of 0.0550 C and a second object that has a charge of 0.110 C exert a force of N on each other. Find the distance between the objects. Use N⋅m2/C2 for the value of Coulomb’s constant. Give your answer to three significant figures.

• A 0.150 m
• B 0.172 m
• C 0.0224 m
• D 0.00163 m
• E 0.0404 m

Q9:

An object with a charge of mC is positioned 1.5 mm directly above an object with a charge of mC, as shown in the diagram. On either side of the positively charged object, there is another object; each of these objects is 2.5 mm away and each with a charge of mC. Find the magnitude of the net electrical force on the negatively charged object. Use N⋅m2/C2 for the value of Coulomb’s constant. Give your answer to two significant figures.

• A N
• B N
• C N
• D N
• E N

Q10:

Two positively charged spheres are separated by a distance of 3.2 mm, as shown in the diagram. One sphere has double the charge of the other sphere. The sphere with the smaller charge has a force of 24 mN exerted on it. Find the charge of the less charged sphere. Use N⋅m2⋅C−2 for the value of Coulomb’s constant. Give your answer to two significant figures.