What is equal to 1 hector area

In a system, when potential energy decreases, then entropy also decreases. true false

An ideal polarizer with its transmission axis rotated 30 degrees to the vertical is placed in a beam of unpolarized light of intensity 10w/m^2. after passing through the polarizer, what is the intensity of the beam? a. 8.7 w/m^2 b. 7.5 w/m^2 c. 5.0 w/m^2 d. 10 w/m^2 e. 2.5 w/m^2

Why is the energy that results from a roller coaster's position at the top of a hill referred to as potential energy?