Two cars are racing to an intersection. Car A is driving East at 90km/h and Car B is driving North East at 29m/s. Neither one is committed to stopping so a collision occurs and Car A ends up travelling 18m/s[E30°N]. If Car A has a mass of 2500 kg and Car B has a mass of 1800 kg, what is the final velocity of Car B? Is the collision elastic?

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?