Acar that increases its speed from 20km/h to 100km/h undergoes what acceleration

A car that increases its speed from 20 km/h to 100 km/h undergoes positive acceleration.

In fact, acceleration is defined as:

where v is the final velocity, u is the initial velocity, and t is the time taken. t has always positive sign, and in this case, the final velocity (v=100 km/h) is greater than the initial velocity (u=20 km/h), so the numerator is positive and therefore the acceleration is positive.

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.

2.6 and i can kick good lol