Translate into scientific notation?

[KraYzie]

I pretty much know how to solve this problem, but I have a simple question.

The question asks a charge of +45 uC (u is coefficient of friction and C is Columb). Now what would that translate into scientific notation?

Because I know 3 uC equals 3.0 x 10^-6, but what about double figures? Thanks

 

[Kurdt]

Well you could write it as 45 x 10^-6. standard notation would be 4.5 x 10^-5. The mu in the units has nothing to do with the coefficient of friction. It denotes micro which means 1 x 10^-6 times the units. In your question for example the units are microcoulombs which are 1 millionth of a coulomb. A micrometer is 1 millionth of a meter.

 

[KraYzie]

why does 3uC equal 3 x 10^-6?

 

[Kurdt]

Like I've said the u (mu) that joins onto the units means that they are a millionth of a Coulomb. So in SI units 3uC are 3x10^-6 Coulomb's. It makes it easier to write down small and large numbers because you don't have to add the x10 stuff.