What are the correct units for acceleration if I used Kg and N?

Light that is polarized along the vertical direction is incident on a sheet of polarizing material. only 96% of the intensity of the light passes through the sheet and strikes a second sheet of polarizing material. no light passes through the second sheet. what angle does the transmission axis of the second sheet make with the vertical?

The diagram shows a series of volcanic island and a hot spot determine the direction of movement of the tectonic plate that for the island

What are two different ways you could find the value of a? explain these methods.