Anet force of 30 n gives a stone an acceleration of 5 m/s. calculate the mass of the stone

6Kg. A stone with a net force of 30N and an acceleration of 5 m/s² has a mass of 6Kg.

The key to solve this problem is using Newton's Second Law F = m.a

Clear m for the equation:

m = F/a

Solving with F = 30N, and a = 5 m/s²

m = 30N/5m/s²

m = 6Kg

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.