16. Why does the number of carts matter when designing a roller coaster track? (Hint: PE = mass x gravity x height and KE = /2 mass x velocity ^2) Choose 2 correct statements.

A. Adding carts increases the mass and decreases the total energy in the system.

B. Adding carts increases the mass and increases the total energy in the system.

C. Removing carts increases the mass and decreases the total energy in the system.

D. Removing carts decreases the mass and decreases the total energy in the system.

Answer B. Adding carts increases the mass and increases the total energy in the system.

Explanation:

By adding carts, the mass of the system is larger, and therefore, both the potential energy and the kinetic energy of the system will increase, thus contributing to larger final velocities as the carts roll down the tracks.

The correct answer is therefore the one shown in answer B:

Adding carts increases the mass and increases the total energy in the system.

1/0.14nm = 10^10/1.4 a lot

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.