explain what additional information you would need to calculate the mechanical energy of a book that was lifted to a height of 3.0 meters. in your answer, write out any formulas you need to compute mechanical energy. (please answer this very quickly)

With i really need the correct answer!

Unpolarized light falls on two polarizer sheets whose transmission axes are at right angles. a third polarizer is placed between the first two so that its axis makes a 52-degree angle with the axis of the first polarizer. a) what fraction of the incident light intensity is transmitted through the first polaroid? b) what fraction of the incident light intensity is transmitted through the second polaroid? c) what is the angle of polarization of the light that enters the third polaroid? d) what fraction of the incident light intensity is transmitted through the third polaroid. e) what happens if the middle polaroid is removed?

What effects result when there is an impact between earth and an asteroid? check all that apply. a. massive flooding. b. extinction of many life forms. c.major earthquakes change in average global temperature. d. giant dust cloud