A30 ton rail car and a 90 ton rail car, initially at rest, are connected together with a giant but massless compressed springbetween them. when released, the 30 ton car is pushed away at aspeed of 4.0 m/s relative to the 90 ton car. what is the speed ofthe 30 ton car relative to the ground?

V2 = 1.33m/s

Explanation:

M1 = 30 ton

M2 = 90 ton

V1 = 4 m/s

V2 = ?

Assumption: momentum conserved, no friction

initial momentum = final momentum = 0  

momentum : p = MV

(M1*V1) - (M2*V2) = 0

V2 = (30*4)/90 = 1.33m/s

V2 = 1.33m/s

Explanation:

M1 = 30 ton

M2 = 90 ton

V1 = 4 m/s

V2 = ?

Assumption: momentum conserved, no friction

initial momentum = final momentum = 0  

momentum : p = MV

(M1*V1) - (M2*V2) = 0

V2 = (30*4)/90 = 1.33m/s

answer: i don't know the answer good luck

explanation:

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.