# Electricity: Static Electricity

## Static Electricity: Audio Guided Solution

#### Problem 25: Three charges are arranged as shown in the diagram at the right.

GIVEN:
Q1 = -15 nC
Q2 = +14 nC
Q3 = +11 nC
1 nC = 1 nanoCoulomb = 1x10-9 C

a. Determine the magnitude and direction of the force exerted by Q1 upon Q2.
b. Determine the magnitude and direction of the force exerted by Q3 upon Q2.
c. Determine the magnitude and direction of the net electrostatic force on Q2.

## Audio Guided Solution

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## Habits of an Effective Problem Solver

• Read the problem carefully and develop a mental picture of the physical situation. If necessary, sketch a simple diagram of the physical situation to help you visualize it.
• Identify the known and unknown quantities; record them in an organized manner. A diagram is a great place to record such information. Equate given values to the symbols used to represent the corresponding quantity - e.g., Q1 = 2.4 μC; Q2 = 3.8 μC; d = 1.8 m; Felect = ???.
• Use physics formulas and conceptual reasoning to plot a strategy for solving for the unknown quantity.
• Identify the appropriate formula(s) to use.
• Perform substitutions and algebraic manipulations in order to solve for the unknown quantity.