In order to produce artificial gravity a large cylindrical space station is spinning in space. If the radius of the space station is 70 m, with what angular velocity should the space station spin in order to provide a gravitational acceleration for the occupants of 9.81 m s -2? If the mass of the space station is 60 tonnes, what is the kinetic energy of the spinning space station?

Amichelson interferometer operating at a 600 nm wavelength has a 3.02-cm-long glass cell in one arm. to begin, the air is pumped out of the cell and mirror m2 is adjusted to produce a bright spot at the center of the interference pattern. then a valve is opened and air is slowly admitted into the cell. the index of refraction of air at 1.00 atm pressure is 1.00028.how many bright-dark-bright fringe shifts are observed as the cell fills with air?