The height of the washington monument is measured to be 170 m on a day when the temperature is 35.0ºc. what will its height be on a day when the temperature falls to –10.0ºc ? although the monument is made of limestone, assume that its thermal coefficient of expansion is the same as marble’s

   169,98 m

Explanation:  The final height Lf will be calculated according to a formula that includes a change in length, that is height ΔL, while the initial length is L₀.

Lf = L₀ + ΔL

Change in length i.e. height ΔL, depend on the change in temperature. The α linear expansion coefficient is also used  incorporating material characteristics and their relationship to temperature change, while the change in temperature is ΔT.

α = 2,5 · 10 ⁻⁶ /°C  for marble

We will express the change in length ΔL as the product of the initial length L₀, the alpha coefficient and the temperature change ΔT.

ΔL = α · L₀ · ΔT =  2,5·10⁻⁶ · 170 · 45° =  - 0.019125 m

So that the final length Lf:

Lf = L₀ + ΔL = 170 - 0.019125 = 169,98 m

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.