Physlet Illustration: Electric Charges

 

 

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In this simulation, four charged particles are shown, along with a vector representing the net electric force experienced by each charge. Charge 1 has a value of +2 mC. What are the signs of the other charges? 

Hints:

  1. Drag the charges around and watch how the force on each charge varies as it comes near to each other charge.
  2. As you drag a charge, its position coordinates and the magnitude of the force it experiences are displayed.
  3. Since the forces on one charge from all other charges add to give the net force, you may need to isolate the charges one pair at a time.
  4. Knowing that like charges repel and unlike charges attract, what is the sign of each charge?
  5. By comparing the magnitudes of the forces between pairs of charges at the same distance from each other, can you determine the magnitudes of the charges 2, 3 and 4?

Reference

See Walker, Section 19-1

Illustration written by Steve Mellema