1. Electric Force Classwork
Tuesday, August 19, 2014
IB Physics SL Year Two

2. Question #1
Two 1.0 kg masses are 1.0 m apart on a frictionless surface. Each has +1.0 µC of charge.
What is the magnitude of the electric force on one of the masses? 9.0x10-3 N
What is the initial acceleration of each mass if they are released and allowed to move? 9.0x10-3 m s-2

3. Question #2
Two small plastic spheres each have a mass of 2.0 g and a charge of nC. They are placed 2.0 cm apart.
What is the magnitude of the electric force between the spheres? 5.6x10-2 N
By what factor is the electric force on a sphere larger than its weight? 2.8

4. Question #3
A small plastic sphere with a charge of -5.0 nC is near another small plastic sphere with a charge of -12 nC. If the spheres repel one another with a force of magnitude 8.2x10-4 N, what is the distance between the spheres? 2.6x10-2 m

5. Question #4
What is the magnitude and direction of the electric force on charge A? 0.0 N, at equilibrium
1.0 nC
-1.0 nC
4.0 nC A + B - C +
1.0 cm
1.0 cm

6. Question #5
Charge q2 experiences no net electric force. What is q1? 8.0x10-9 C q1
-2.0 nC q2 + - +
10 cm
10 cm