11. (a)What downward force is acting on you when you go down a waterslide? (b)What type of friction is present? (c)If the waterslide were dry explain what type of friction in would be and (d)how that
changes your speed? (4 points)

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?