A car starts at the top of a hill with 200 J of energy, and rolls down a frictionless surface. The isolated system consists of the car, hill, and earth. What happens to the energy of the system as the car moves down the hill?

The total energy stays the same but is converted from being stored as kinetic energy into elastic potential energy as it moves.

The total energy stays the same but is converted from being stored as gravitational potential energy into kinetic energy of the car as it moves.

The total energy decreases and is converted from being stored as gravitational potential energy into kinetic energy as it moves.

The total energy decreases and is converted from being stored as elastic potential energy into kinetic energy as it moves.

The total energy stays the same but is converted from being stored as gravitational potential energy into kinetic energy of the car as it moves.

Explanation:

the law of conservation of energy states that the total energy of an isolated system remains constant, and since it is gaining speed that energy will be kinetic

where’s the list ? the question is incomplete

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.