Atrack begins at 0 meters and has a total distance of 100 meters. juliet starts at the 10-meter mark while practicing for a race.
after running 45 meters, how far is she from the beginning of the track?
10 meters
35 meters
45 meters
55 meters

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?