Question

the net electric force acting on each of the three objects below is sketched as a green arrow. for example, if the green arrow points to the left the object feels a net electric force pushing it to the left. if there is no green arrow, the object feels no net electric force. use this information to assign an electric charge to each object. that is, decide whether each object has a positive electric charge, a negative electric charge, or is neutral. note for advanced students: there may be more than one correct answer.

Explanation:

Step1: Recall electric - force rules

Like charges repel and opposite charges attract. A neutral object experiences no electric force in the presence of other charged objects (except for very weak polarization - related forces which we ignore here).

Step2: Analyze left - most object

The left - most object has a net force to the left. Assume there is a charged object on its left or right. If there is a positive charge on its right, it will be repelled to the left. Or if there is a negative charge on its left, it will be attracted to the left. So the left - most object could be positive.

Step3: Analyze middle object

The middle object has a net force to the right. If the left - most object is positive, to repel the middle object to the right, the middle object must be positive. Or if there is a negative charge on the right of the middle object, it will attract the middle object to the right.

Step4: Analyze right - most object

The right - most object has no net force, so it is neutral.

Answer:

Left - most object: Positive; Middle object: Positive; Right - most object: Neutral