Aspacecraft is launched from earth toward the moon. where will the spacecraft be when the gravitational forces acting on it are equal? a. closer to earth than to the moon because the moon has greater mass than earth. b. closer to the moon than to earth because the moon has greater mass than earth. c. closer to earth than to the moon because earth has greater mass than the moon. d. closer to the moon than to earth because earth has greater mass than the moon.

D. Closer to the moon than to Earth because Earth has greater mass than the moon.

Explanation:

The force of gravity being exerted by any object depends on its mass. More the mass greater will be force of gravity. Also, the range of the gravitational force will be more for the object with more mass.

Here since Earth is heavier than the Moon, its gravitational force will be huge even at large distances as compared to the Moon.

That is why when the spacecraft experiences equal gravitational force it will be closer to the Moon than Earth as Earth is heavier than Moon.

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.

it's a b and