Which of the following represents a case in which you are not accelerating? -driving 60 miles per hour around a curve -going from 0 to 60 miles per hour in 10 seconds -slamming on the brakes to come to a stop at a stop sign -driving in a straight line at 60 miles per hour

Driving in a straight line at 60 miles per hour

Explanation:

In the first case there's an acceleration that modifies the direction of the movement.

In the second case there's a lineal acceleration that increases the speed of the car.

in the third case there's a negative acceleration that reduces the speed of the car.

On the third case the speed is constant so the acceleration is 0 mi/s^2

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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.