Static Electricity - Mission SE2 Detailed Help

Balloons X , Y and Z are suspended from strings as shown below. Positively charged balloon X attracts balloon Y while balloon Y attracts balloon Z. Balloon Z ____. List all that apply in alphabetical order with no spaces between letters.

Charge Interactions
Charged objects show a noticeable interaction with other surrounding objects. The cause of the interaction can be summarized by one of the following three statements:
  • Oppositely charged objects attract each other.
  • Like-charged objects repel each other.
  • Any charged object - whether positive or negative - will attract a neutral object.

Minds On Physics should be a minds on activity. You have to use your noodle(that's your brain) to be successful. This question in particular should cause a little cranial activity. Balloon X is charged and attracts balloon Y. From this observation alone, you might think that balloon Y is either neutral or charged the opposite of balloon X (see Know the Law section). So if balloon X is charged positively, balloon Y is either negatively charged or neutral - and you don't have sufficient evidence to conclude which it is. But the focus of the question is on balloon Z. Balloon Z attracts balloon Y. If Y is charged negatively, then balloon Z could be either positively charged or neutral. But you don't know for sure that balloon Y is charged; you might recall that it was just written that balloon Y could be neutral. So if balloon Y were neutral and attracted balloon Z, balloon Z could be either positively charged or negatively charged. From this reasoning, you can conclude three possibilities for balloon Z.

When reviewing the three different types of charge interactions (see Know the Law section), you will notice that two of the interaction types involve an attraction of two objects. Oppositely charged objects indeed attract. But that is not the only cause for two objects attracting each other. A charged object and a neutral object will also attract. So knowing that two objects attract each other is NOT sufficient evidence to conclude that both objects are charged. Don't be fooled! If two objects attract, then it is possible that one object is charged and the other is electrically neutral.