What part of a wave is a measure of the amount of energy it carries

Why did ptolemy have to introduce multiple circles of motion for the planets instead of a single, simple circle to represent the planetâs motion around the sun?

Apackage of supplies is dropped from a plane, and one second later a second package is dropped. neglecting air resistance, the relative velocity of the 1st package viewed from the second will 56) a) increase. b) be constant. c) be zero. d) depend upon their weight. e) decrease

The transfer of heat through the movement of a gas or liquid a. convection b. conduction c. radiation