A closed system consists of a pendulum that is swinging back and forth. If the kinetic energy of the pendulum increases, what else must happen to the
energy of the system?
A. Its total mechanical energy must increase.
B. Its total mechanical energy must decrease.
C. Its gravitational potential energy must increase.
D. Its gravitational potential energy must decrease.

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 does si stand for, when referring to a system of measurement

Chameleons catch insects with their tongues, which they can rapidly extend to great lengths. in a typical strike, the chameleon's tongue accelerates at a remarkable 220 m/s2 for 20 ms, then travels at constant speed for another 30 ms.