A30-kg girl and a 25-kg boy face each other on friction-free roller blades. the girl pushes the boy, who moves away at a speed of 1.0 m/s. the girl's speed is

Mercury turns to a vapor at 629.88 k. how much heat is lost when 75.0 g of mercury vapor at 650 k condenses to a liquid at 297 k?

What causes the appearance of lines in a emission spectrum

Spaghetti sauce can be high in sodium. what is a good guideline for mg of sodium per half cup serving? a. less than 1 mg b. less than 800 mg c. less than 700 mg d. less than 400 mg