A football is kicked off the ground a distance of 50 yards downfield. Neglecting air resistance, which of the following statements would be INCORRECT when the football reaches the highest point? (A) all of the balls original kinetic energy has been changed into potential energy.
(B) the balls horizontal velocity is the same as when it left the kickers foot.
(C) the ball will have been in the air one-half of its total flight time.
(D) the ball has an acceleration of g.
(E) the vertical component of the velocity is equal to zero.

b) phosphorus pentoxide

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.

the answer is 12 as i may remember

: )