Answer:
1020 km
Explanation:
A complete rotation of the wheel equals a distance of 1 circumference.
The circumference is

where <em>d</em> is the diameter of the wheel.
300,000 rotations = 
In kilometers, this is = 1017876/1000 km = 1020 km
Answer:
Light waves slow down as they travel from gas to solid.
Explanation:
The speed of light is often quoted with reference to a vacuum. Light travels fastest in a vacuum and in a gas.
When light travels through other media such as solids or liquids, the speed of light is decreased due to absorption and scattering of photons by molecules as well as remissions.
Hence the speed of light decreases from gas to solid.
They are unproven but accepted as fact.
Many experiments support them but they can be disproven by the results of a single experiment. Until then, they stand.
The third statement is correct.
Pb, if compared to Ca it is less reactive and it is a transition metal, and is highly stable alone.