21. . Suppose you are standing on a frozen lake where there is no friction between your feet and the ice. What can you do to get off the lake? A. Bend over touching the ice in front of you and then bring you feet to your hands. B. Walk very slowly on tiptoe. C. Get on your hands and knees and crawl off the ice. D. Throw something in the direction opposite to the way you want to go.

An inclined plane wrapped around a metal shaft is a a. lever b. screw c. pulley d. wedge

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.

Which of the following changes will result in a stronger electromagnet? a. using fewer coils of wire b. using a higher voltage c. using a shorter nail d. using a longer wire