A brick mason builds a simple machine to lift bricks from the ground up to the second story of a building. The machine requires an input force of 35 N to lift 75 kg (735 N) of bricks. What is the ideal mechanical advantage (MA) of the simple machine? A MA = 0.048 B MA = 2.143 C MA = 35 D MA = 21

A MA = 0.048

Explanation: 35 divided by 735 is equal to 0.048

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.