Arock of mass m is twirled on a string in a horizontal plane. the work done by the tension in the string on the rock is:
a. + (positive)
b. - (negative)
c. 0

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

A1-lb collar is attached to a spring and slides without friction along a circular rod in a vertical plane. the spring has an undeformed length of 5 in. and a constant k =25 lb/ft. knowing that the collar is released from being held at a determine, the speed of the collar and the normal force between the collar and the rod as the collar passes through b.

To fully describe the photoelectric effect, scientists must consider which of the following to be quantized? o a. both light and matter o b. matter only o c. light only o d. neither light nor matter