Unpolarized light of intensity i0 is incident on three polarizing filters. the axis of the first is vertical, that of the second is 43° from vertical, and that of the third is horizontal. what light intensity emerges from the third filter?

To determine the intensity, the key idea is to work through the system filter-by-filter and applying either the one-half rule for unpolarized light or the cosine-squared rule for an already polarized light.

When the light reach the first filter, it is unpolarized, so the intensity is :
            I1 = 1/2 I0                     (One-half rule)

Because the light reaching the second filter is polarized, given 43° angle difference, the intensity is : 
            I2 = I0 cos^2 (angle difference)
                = I0 cos^2 43°
                = 0.535 I0

Lastly, when the light reached the third filter, it is polarized and has angle diference equals to the angle between the second and last filter 47°. Using the same rule, we get :
           I3 = I2 cos^2 47°
               = (0.535 I0) cos^2 47°
               = (0.535 I0) (0.465)
               = 0.249 I0

So, the intensity which emerges is 0.249 I0.

Ifound this answer online hope it

So since the snail is moving at 3.6  miles per hour you multiply by 5280 to change it into feet per hour. so you get 36*528 ft per hour. since there are 3600 seconds in an hour, you divide 36*528 by 3600. so simplifying we get 528/100 which is 5.28 ft per second