Answer to Question #175806 in Physics for Joshua

Question

Coulomb's Law and Net Electric Field

Solve the following word problems. Show complete solutions to your answer.

1. Find the electronic force between charges of +2.0 C and +5.0 C separated by distance of 75 m in a vacuum.

2. Two charge of +8.0 mC and -6.0 mC attract each other with a force of 3.0 x 103 N in a vacuum. What is the distance between the charges?

3. A charge of 12 uC when placed in electric field experiences a force of 648 N. What is the magnitude of the electric field strength?

4. What happens to the force between two charges metal spheres in a vacuum if the charge on each is doubled and the distance between them is multiplied by three?

Answer 1

1)

$$F=9\cdot10^9\frac{2\cdot 5}{75^2}=1.6\cdot10^7\ N$$

2)

$$9\cdot10^9\frac{0.008\cdot 0.006}{d^2}=3\cdot10^3\\d=12\ m$$

3)

$$E=\frac{648}{12\cdot10^{-6}}=5.4\cdot10^{7}\frac{N}{C}$$

4)

$$F=k\frac{q^2}{d^2}\\F'=k\frac{4q^2}{9d^2}=\frac{4}{9}F$$