Your bathroom shower curtain swings toward you in the shower when the water is on full blast. explain.

The water pushes the shower curtain. Push is a force. The water basically thrusts the shower curtain and the curtain will then not stop immediately as it has a bit of braking distance. Then braking distance differs on the total force the water has on the curtain. Simple way: The curtain moves because the water acts as a push to propel the curtain forwards.

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.