Turn friction on, and get the object accelerating with an applied force. Then, take the applied force away. Is there any acceleration? If there is acceleration, what direction is this acceleration in? (Is it going on the same direction as the object’s motion or the opposite direction? How do you know?)

there can be acceleration

Explanation:

because of the friction. If the friction and applied force is nowhere then it will not move, but if it has a friction it will move but not in the same direction it can only move slightly or really move. based on me only

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.