Acar is stopped at an entrance ramp to a freeway; its driver is preparing to merge. at a certain moment while stopped, this driver observes a platoon of vehicles a distance x0 upstream and initiates the merge maneuver. the platoon approaches the entrance ramp at a constant speed v. the stopped car can accelerate from speed 0 to v at uniform acceleration rate a. find the latest time at which the stopped car can safely start the merge maneuver; i. e., derive an expression for the "latest safe start time" in terms of the variables x0, v and a. assume this latest time enables the platoon to maintain its constant speed and "just touch" the merging car's trajectory. ignore the physical dimensions of the car.

a.) is the correct answer.

explanation:

a. are

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.