Two planets travel in circular orbits about a star at radii of ra = 2r and rb = r, respectively. What is the ratio of their periods ta/tb?.

Examine the nuclear reacti why is this classified as a nuclear reaction rather than a chemical reaction? it is not balanced. a new compound is formed. a change has occurred in a nucleus. a new element has been formed.

The movement of electrons between atoms is called an

The flame produced by the burner of a gas (propane) grill is a pale blue color when enough air mixes with the propane (c3h8) to burn it completely. for every gram of propane that flows through the burner, what volume of air is needed to burn it completely? assume that the temperature of the burner is 195.0°c, the pressure is 1.05 atm, and the mole fraction of o2 in air is 0.210.