A 2-kg block A is pushed up against a spring (they are not connected), compressing it a distance = 0.1 m. The block is then released from rest and slides down the 200 incline until it strikes a 1-kg sphere B that is suspended by a 1.0-m inextensible rope. The spring constant k = 800 N/m, the coefficient of friction between A and the ground is 0.30, block A slides from the unstretched length of the spring a distance d = 1.50 m, and the coefficient of restitution between A and B is 0.8. The final angle of the pendulum is intended to be:

answer; i believe the correct answer is (40,000 j) good luck

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.