A railway truck A of mass 2000kg moves westwards with a velocity of 3m. s. it collides with a stationery truck B of mass 1200kg, loaded with electronic equipment of mass 300kg. The two trucks combined after the collision. Ignore the effects of friction. 7.1 wite down magnitude and direction of the 'reaction force ' to the weight of truck A. 7.2 calculate the velocity of truck B after the collision 7.3 calculate the magnitude of the force that truck A exerts on truck B if the collision lasts for 0.5s

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explanation:

i believe the answer is a hope it and is correct

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.