Adriver speeds along a curved road and sees a fallen tree on the road. he applies the brakes but is unable to stop in time. when the car hits the tree, it slows down from 6 meters/second to 0 meters/second. what was the change in velocity during this time? the change in velocity during the collision was   meters/second. need it fast

The change in velocity is the difference of the final velocity and the initial velocity:

0 – 6 = -6 m/s.

i think the answer is a and b

i wish you luck

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.