Q. An airplane flies 200km due west from city Band then 285km in the direction of 28.0 degrees north of west from city B to city C. in a straight-line distance how far is city C from city A?
Q. A device used in radiation therapy for cancer contains 0.50 g of cobalt _27^60 text(Co) (59.933 819 u). The half-life of _27^60 text(Co) is 5.27 yr. Determine the activity of the radioactive material.