Calculate the binding energy per nucleon (in J) for Be and "Be. The atomic masses are 7.016930 u for Be, and 9.012182 u for "Be. (Enter unrounded values. Assume that the mass of H = 1.007825 u, mp=1.007275 u, m = 1.008666 u, and me = 0.000549 u, respectively.) 7Be 9Be XJ/nucleon XJ/nucleon

A sample of rock was found to contain 8.23 mg of rubidium-87 and 0.47 mg of strontium-87.. (a) Calculate the age of the rock if the half-life of the decay of rubidium by emission is 4.71010 y. (b) If some S3887r was initially present in the rock, would the rock be younger, older, or the same age as the age calculated in (a)? Explain your answer.