A bullet is shot horizontally from the edge of a tall cliff. At the instant the bullet is shot, a rock is dropped from the same height. Neglecting air resistance, which one will hit the ground first

The bullet and the rock will hit the ground at exactly the same time

Explanation:

Due to the gravitational forces, defined by Newton's law of gravitation, the acceleration of objects towards the center of the Earth is constant and equal to the acceleration due to gravity, g ≈ 9.8 m/s².

Therefore, given that the initial vertical velocity, u, of the rock and the bullet are both equal to zero, from the following equation of motion, we have;

s = u×t + 1/2·g·t²

t = Time

s = The height from which the bullet is fired and the rock is dropped

s = 0×t + 1/2 × 9.8 × t²

s = 1/2 × 9.8 × t²

t  = √(2 × s/9.8)

Therefore, the time to hit the ground is only dependent on the height from which the bullet and the rock were allowed to fall freely.

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.