Aperson weighing 900 n is standing on snowshoes. each snowshoe has area 2500 cm^2. what is the pressure exerted by each individual snow shoe on the snow?

a) 0.18 n/m^2
b) 0.36 n/m^2
c) 1800 n/m^2
d) 3600 n/m^2

is it 3600 n/m^2?

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.

3. dark matter

empty space could also be a simple vacuum