An engineer is designing a runway. She knows that a plane, starting at rest, needs to reach a speed of 140mph at take-off. If the plane can reach this take-off speed in 60.0s, how far will the plane travel before take-off. Assume the plane increases speed steadily. How far does the plane need to travel during take-off (in given units)?

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?