When you ride a roller coaster that makes sharp turns ,you feel yourself being pushed to one side . use newton’s first law of motion to explain this phenomenon

Explanation:

Newton's first law says that an object in motion stays in motion, and an object at rest stays at rest, until acted upon by an unbalanced force.

When a roller coaster makes a sharp turn, your body continues going straight until the seat belt pushes you and changes your direction.  If the roller coaster didn't have seat belts, you'd slide off and continue moving straight.

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.

i would say