Three Pith Balls Supported by Insulating Threads Hang from a Support

question 19

Multiple Choice

Three pith balls supported by insulating threads hang from a support. We know that ball X is positively charged. When ball X is brought near balls Y and Z without touching them, it attracts Y and repels Z. Since pith is an insulating material, we can conclude that

• A) Y has a negative charge.
• B) Z has a negative charge.
• C) Y has a positive charge.
• D) Z has a positive charge.
• E) Z is neutral (has no net charge.)

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Definitions:

Rational Arguments

Reasoning conducted or assessed according to strict principles of validity.

Leucippus

An ancient Greek philosopher, considered one of the earliest proponents of atomism, the theory that the universe is composed of indivisible components.

Vacuum

A space entirely devoid of matter, or having a pressure much lower than atmospheric pressure.

Law of Conservation

A principle stating that in a closed system, mass (in classical physics) or mass and energy (in quantum physics), cannot be created or destroyed, but only transformed or transferred.