Drag the charges around the simulation. The arrow on each charge shows the net force on the charge.

#### Four Charges

Four charges are shown above. How many of them are positive?

- One of them
- Two of them
- Three of them
- All four
- One or three of them, there's not enough information to decide

Charges 1, 2, and 4 have the same sign, while charge 3 has the opposite sign. There is either one positive charge or three positive charges.

There are two kinds of charge, positive and negative. Like charges repel; unlike charges attract.