What does it mean when work is positive? velocity is greater than kinetic energy. kinetic energy is greater than velocity. the environment did work on an object. an object did work on the environment.

As we know by work energy theorem

Work done by all forces = change in Kinetic Energy

here if work done is positive then it means change in kinetic energy will be positive

So work is done on the object which will increase the kinetic energy of that object.

So here to increase the speed we can say that the surrounding is doing some work on it which will increase the speed.

So here correct answer must be

The environment is doing work on it.

C

Explanation:

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.