Akiddie roller coaster car has a mass 100 kilograms. at the top of a hill, it’s moving at a speed of 3 meters/second. after reaching the bottom of the hill, its speed doubles. the car’s kinetic energy at the bottom is its kinetic energy at the top. the car has joules of kinetic energy at the bottom of the hill.

The car’s kinetic energy at the bottom is 4 times its kinetic energy at the top. The car has 1800 joules of kinetic energy at the bottom of the hill.

Explanation:

The kinetic energy of the car is given by:

where m is the mass of the car and v its speed.

First of all, we see that the kinetic energy is proportional to the square of the speed: since the speed of the car at the bottom of the hill is twice the speed at the top of the hill, then the new kinetic energy must be times the kinetic energy at the top.

We can explicitely calculate it by using the formula.

At the top of the hill:

At the bottom of the hill, the speed has doubled, so it is 6 m/s; therefore, the kinetic energy is

answer: strength i guess

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.