Three point charges are arranged in a horizontal line as shown below.

Question

Three point charges are arranged in a horizontal line as shown below. Find the electric forces (in units of kQ²/R²) on the charges given the following: Q₁ = 2 Q, Q₂ = 125 Q, Q₃ = 108 Q, r₁ = 1 R, and r₂ = 5 R. Remember that a positive force points to the right and a negative force points to the left. 

What is the force on charge Q₁ due to Q₂?

 kQ²/R²

Tries 0/2

What is the force on charge Q₁ due to Q₃?

 kQ²/R²

Tries 0/2

What is the force on charge Q₂ due to Q₃?

 kQ²/R²

Tries 0/2

What is the force on charge Q₂ due to Q₁?

 kQ²/R²

Tries 0/2

What is the force on charge Q₃ due to Q₁?

 kQ²/R²

Tries 0/2

What is the force on charge Q₃ due to Q₂?

 kQ²/R²

Tries 0/2

What is the net force on charge Q₁?

 kQ²/R²

Tries 0/2

What is the net force on charge Q₂?

 kQ²/R²

Tries 0/2

What is the net force on charge Q₃?

 kQ²/R²

Tries 0/2

What is the sum of the forces on all three charges?

 kQ²/R²

Answer 1

All the forces should be repulsive since the signs of the charges are the same.

The force on charge a due to charge b is equal and opposite to the force of charge b due to charge a.

For example, the force on Q1 due to Q2, F₂₁ = -(2Q*125Q)/R². This is negative since Q2 is pushing Q1 to the left, and F₁₂, the force on Q2 due to Q1 would be positive since Q1 is pushing Q2 to the right.

The net force on charge 1 would be F₂₁ + F₃₁ and would be negative since both Q2 and Q3 push Q1 to the left.

The net force on charge 2 would be F₁₂ - F₃₂, positive if F₁₂ is greater than F₃₂ and negative if vice versa.

The sum of forces on all three charges would be zero just due to the equal and opposite effect.

The information above should be sufficient to answer all the questions.