Why do trucks need a runaway ramp

What happens to light waves from a star as the star moves away from earth?

Unpolarized light of intensity i_0=750w/m^2 is incident upon two polarizers. after passing through both polarizers the intensity is i_2=280w/m^2. (a) what is the intensity of the light after it passes through the first polarizer in w/m^2? (b) write an equation for the angle between the polarizers in terms of the initial (i_0) and final (i_2) intensities. (c) find the angle between the polarizers in degrees.

Acar drives toward the right over the top of a hill, as shown below. which arrow represents the centripetal acceleration? w x y z