Kiku and Alex are wearing rollerskates. Kiku is right behind Alex, and both skaters are standing still. Alex weighs more than Kiku. If Kiku gives Alex a forward push, which of the following will be true after the push? Assume that this is a closed system and friction can be ignored. A.
Kiku's momentum and Alex's momentum will add up to zero.
B.
Kiku's velocity and Alex's velocity will add up to zero.
C.
Alex's speed will be greater than Kiku's speed.
D.
Alex's momentum will be greater than Kiku's momentum.

the answer would be c

an electric circuit

the duration of a photographic flash is related to an rc time constant, which is 0.100 μs for a certain camera.

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.