Asample of phosphorus-32 has a half-life of 14.28 days. if 55 g of this radioisotope remain unchanged after approximately 57 days, what was the mass of the original sample?

2points what is the job of a scientist? a. to answer ethical questions. b. to write laws based on his or her knowledge. c. to ask and answer scientific questions. d. to ignore facts that do not support his or her theory.

Given that 1 mi = 1760 yd, determine what conver- sion factor is appropriate to convert 1849 yd to miles; to convert 2.781 mi to yards.

Which of the following units is not an official si unit