# Static Electricity

You rub your feet on the carpet in your warm living room on a cold winter day. You know you have gained static electrical charge on your body. You decide to touch your sister to shock her. Your sister knows that in order to reduce the electrical shock she will feel when you touch her, she
(A)must stand very still
(B) hold on to a doorknob
(C)jump up and down at exactly 60 Hertz
(D)rub her feet on the carpet

I have narrowed this down to answers B and D. I am leaning toward answer B, because if the sister rubs her feet on the carpet, as in answer D, there still might be a charge differential between the two people and therefore there would still be a shock. I think, but am not sure, that B would "ground" the charge. Please help!

## Answers and Replies

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Dick
Science Advisor
Homework Helper
If (B) would ground her, she would still get a shock, right? As would you, so that might be ok. Suppose she could charge herself up to the same potential as you? Then what would happen? How might she do this? I think you know the correct answer.

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I'm just confused because even if she rubs her feet on the carpet, there is no guarantee that she will charge herself to the same potential as you.

On a related note, when you ground yourself you produce an electric shock? Does this occur because you are transferring a charge back to the earth?

Dick
Science Advisor
Homework Helper
Nope, no guarantee. But the less the potential difference, the less the shock. Shocks are mutual, the same current passes through both parties. The trick to shocking someone is that you expect it and they don't. It's largely psychological. Grounding one doesn't make much difference.

I'm just confused because even if she rubs her feet on the carpet, there is no guarantee that she will charge herself to the same potential as you.
True, but your original question said "reduce" not eliminate.