Speed deamplifier. block 1 of mass m1 slides along an x axis on a frictionless floor at speed 4.00 m/s. then it undergoes a onedimensional elastic collision with stationary block 2 of mass m2 = 2.00m1. next, block 2 undergoes a one-dimensional elastic collision with stationary block 3 of mass m3 = 4.00m1. (a) after all the collisions, what is the speed of block 3?

photocells convert light energy to electricity

i think the answer would be b

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.