A spaceship takes a straight line path from the earth to the moon, a distance of about 400000 km. Suppose it accelerates at 5 m/s2
for the first 10 min of the trip, then travels at constant speed until the
last 10 min, when it accelerates at – 5 m/s2
, just coming to rest as it reaches the moon (a) What is the
maximum speed attained? (b) What total time required for the trip?

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide

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.