What is the period of our orbital motion about the center of the galaxy in earth years?

225 -250 million Earth-years

Explanation:

A galactic year or cosmic year is the time it takes for the Sun (and the solar system) to make an orbit around the center of the galaxy (Milky Way). The solar system travels at a speed of 828,000 Kilometers per hour (230 ).

 So the time it takes to make this turn, measured in Earth years, should be between 225 and 250 million years.

they are non-matter

explanation:

they are non-matter. basically, any type of energy or any abstract concept is an example of something that does not matter. other examples include dreams, magnetism, radio, and hate

a) electrical > light, sound, and thermal< < < <

) the mechanical energy of the firefighter moving.< < < < a) electrical > light, sound, and thermal< < < <

c) both a and b.