words - Expressing scientific notation and units in speech

I've got two related questions:

1) How do you say numbers in scientific notation in Japanese? For example, 3x10⁸ is spoken in English as "three times ten to the eight". Do negative exponents works the same as ordinary negative numbers (i.e. prefix with マイナス)?

2) How do you say the units? For example m s^-1 ("meters per second" - you get no prize for guessing why I'm asking ;) ), or more complicated examples like kg m² s^-2 K^-1 ("kilogram metres squared per second squared kelvin").