Please help time is running out

Atruck with 34-in.-diameter wheels is traveling at 55 mi/h. find the angular speed of the wheels in rad/min, *hint convert miles to inches & hours to minutes:

Acopper sheet has a volume of 100 cm³. if the density of copper is 8.9 g/cm³, what is the mass of the sheet? a. 11 g b. 8.9 g c. 189 g d. 890 g

What would occur if the index of refraction of a material was less than n=1? the speed of light would increase to a speed larger than the maximum speed of light in a vacuum. the light wave would not bend at all though the material. the light wave would not be able to refract and would instead reflect off of the material. the speed of light would reduce to values close to 0 m/s.