# Homework Help: PhysicsQuestions help.

1. Jan 17, 2006

### wasdwasd

(a) Explain why it is possible for an air passenger to get an electrical shock when he touches the knob of the toilet door in a high altitude flying aeroplane

(b) Why do some car owners fix to their cars a peice of fine chain which drags on the road?

2. Jan 17, 2006

### Staff: Mentor

Do you understand how static electricity works, and how the static separation of charge can happen?

3. Jan 17, 2006

### BobG

b is due to modern chemistry. Tires are made with more silica (a non-conductive material) and less carbon (a more conductive material). This increases gas mileage, but reduces the ability of the car to dissipate static electricity.

If you look on the internet, you can find a couple references to this problem. I doubt they'll provide the complete answer. You probably need an explanation of what causes static electricity to build up in the first place (something your book should tell you - the airplane and car problem just provides a real life example to think about).

The articles:

http://www.cartalk.com/content/columns/Archive/1997/June/07.html [Broken]
http://www.cartalk.com/content/columns/Archive/1997/October/01.html [Broken]
http://www.popularmechanics.com/automotive/sub_care_clinic/1272106.html?page=1&c=y [Broken]

All three articles seem to be obsessed with polyester leisure suits.

In the old days, fuel trucks used to drag chains under their trucks since an electrical spark from static electricity could have a much bigger impact than just pain to the driver (it was more a reaction to a lawsuit than a realistic probability of explosion). Today, the 'fine chains' are rubber strips with wire embedded in them (rubber strips are quieter than chains).

Last edited by a moderator: May 2, 2017