8. A train that is 268.7 m long undergoes constant acceleration the moment the last car (end of the train) is outside of the station, how far is the front of the train from the station after 25.0 s
if its initial speed before acceleration is 4.48 m/s and its final speed is 27.4 meters per second?
0678 m
O 399 m
O 663 m
0 667 m

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.