Question

hiro rubs an inflated balloon on his hair, and his hair sticks to the balloon. as he moves the balloon away from his head, how does the electric force change?
the electric force increases because the balloon loses its charge.
the electric force increases because the distance increases
the electric force decreases because the distance increases.
the electric force decreases because his hair loses its charge.

Explanation:

Step1: Recall Coulomb's Law

Coulomb's Law states that the electric force \(F = k\frac{q_1q_2}{r^2}\), where \(k\) is a constant, \(q_1\) and \(q_2\) are the charges, and \(r\) is the distance between the charges.

Step2: Analyze the effect of distance

When Hiro moves the balloon away from his head, the distance \(r\) between the charges (on the balloon and on the hair) increases. Since \(F\) is inversely proportional to \(r^2\) (\(F\propto\frac{1}{r^2}\)), as \(r\) increases, the electric force \(F\) decreases. The charges \(q_1\) (on balloon) and \(q_2\) (on hair) do not change just because the distance changes.

Answer:

The electric force decreases because the distance increases.