A 1.40-kg ball bounces off a vertical wall. The ball approaches the wall at 9.70 m/s to the east and leaves the wall with the same speed. What is the change in momentum that the wall imparts to the ball

Light from two different sources are incident upon the same side of a polarizing filter. light from one source is polarized with total intensity ip, while light from the other source is unpolarized with total intensity iu. as you rotate the polarizing filter through 360 degrees, the intensity of the transmitted light on the other side varies by a factor of 9. what is the relative intensity of the initial polarized source to the unpolarized source, or ip/iu?