It is almost time for the summer Olympics. The Olympic hammer throw is a throwing event where the object is to throw a heavy metal ball attached to a wire and handle. The name hammer throw comes from an older contest where men threw a sledge hammer. The hammer have different weights, ranging from 16 pounds down to 8 pounds. Imagine there are four hammers to throw: 16, 12, 10, and 8 pounds. You want to reach the same distance which each hammer. You would need the least force to throw which hammer?

see earlier

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.