An initial sample of 502 g of a radioactive substance decays according to the function A ( t ) = 502 e − 0.033 t where t is given in years. (a) How many grams of the substance will remain after 68 years? Round your answer to one decimal place.

What is the typical rotational frequency frot for a molecule like n2 at room temperature (25∘c)? assume that d for this molecule is 1å=10−10m. take the total mass of an n2 molecule to be mn2=4.65×10−26kg. you will need to account for rotations around two axes (not just one) to find the correct frequency. express frot numerically in hertz, to three significant figures.