Astudent solving for the acceleration of an object has applied appropriate physics principles and obtained the expression a=a1+fm where a1=3.00 m/s^2, f=12.0kg. m/s^2 and m=7.00kg. (a) first, which of the following is the correct step for obtaining a common denominator for the two fractions in the expression in solving for a? finding acceleration.

e/c, where e is its total energy

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.