Astreet light is at the top of a 10 ft tall pole. a woman 6 ft tall walks away from the pole with a speed of 8 ft/sec along a straight path. how fast is the tip of her shadow moving when she is 40 ft from the base of the pole?

the shadow is moving with 12ft/s from the woman

Explanation:

let the distance from the pole to the shadow tip be L

hence the shadow is moving with 12ft/s from the woman

answer: a. same unit

explanation:

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.