You are driving north through an intersection in a 55 $mi/hr$ speed zone, when the local chief of police, who is driving his new cadillac and approaching the intersection from the west, hits you broadside. the two cars stick together and skid a distance 40.9 $m$ with locked wheels at an angle of 68.5° to the east of north. the mass of your car is 1461.0 $kg$ while the cadillac has a mass 2077.0 $kg$. the coefficent of sliding friction is 0.70. the chief of police is angry that you have damaged his new cadillac and gives you a ticket for speeding. the local judge is going to believe his chief of police rather than some out-of-town student. you realize that the knowledge you learned in your physics course is your only hope for acquittal. compute the speed of the chief of police immediately prior to the collision.

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.

490 n

f=125n a=2.5m/s2