If a hot air balloon is seen rising above the top of a hill, what is the top of the hill called?

In 1995 a research group led by eric cornell and carl wiemann at the university of colorado successfully cooled rubidium atoms to the 20-200 nk temperature range. assuming (incorrectly) that the rubidium atoms behave liké particles of a classical ideal gas, calculate the rms speed of a rubidium atom at a temperature of 112.0 nk. in the experiments one particular isotope of rubidium was used, rubidium-87. the molar mass of this isotope is 86.91 q/mol. tries 0/20 submit answer

Carbon-14 is a radioactive element that undergoes beta decay. which force is responsible for allowing carbon-14 to become stable? electromagnetic gravitational weak nuclear strong nuclear

What kind of simple machine is a catapult?