Bryan allen pedaled a human-powered aircraft across the english channel from the cliffs of dover to cap gris-nez on june 12, 1979. allen encountered a headwind averaging 2.00 m/s almost precisely in the opposite direction of his motion relative to the earth. what was the magnitude of his average velocity relative to the air? (in m/s)

b.transmitters send radio waves, and receivers capture radio waves.

dang that balls went far

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.

i believe the answer is electric potential.

explanation: