An engineer is designing a runway. She knows that a plane, starting at rest, needs to reach a speed of 140mph at take-off. If the plane can reach this take-off speed in 60.0s, how far will the plane travel before take-off. Assume the plane increases speed steadily. How far does the plane need to travel during take-off (in given units)?

this is poiselle's equation from fluid mechanic in physics. mech eng

measure their densities same density, same sub

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.