The 300-series Shinkansen trains consist of 16 aluminum cars with a combined mass of 7.10 X 105 kg. The reduction in mass from the 100- series enables the 300-series trains to reach top speed of 270 km/h. What is the momentum of one of these trains at its top speed? Is the
momentum of a 300-series train greater or less than the momentum of a 100-series train traveling at its top speed?

a=d/t

a="triangle"v/t

explanation:

a = acceleration

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.

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray