Radioactive isotopes are often introduced into the body through the bloodstream. their spread through the body can then be monitored by detecting the appearance of radiation in different organs. 1311, a b- emitter with a half-life of 8.0 days is one such tracer. suppose a scientist introduces a sample with an activity of 375 bq and watches it spread to the organs. assuming that the sample all went to the thyroid gland, what will be the decay rate (activity) in that gland 24 days later? if the subject's thyroid has a mass of 20 grams, and each b- is of energy 5 kev, what is the total dose of radiation the thyroid receives?

Abasketball star covers 2.65 m horizontally in a jump to dunk the ball. his motion through space can be modeled precisely as that of a particle at his center of mass. his center of mass is at elevation 1.02 m when he leaves the floor. it reaches a maximum height of 1.90 m above the floor and is at elevation 0.910 m when he touches down again. (a) determine his time of flight (his "hang time"). (b) determine his horizontal velocity at the instant of takeoff. (c) determine his vertical velocity at the instant of takeoff. (d) determine his takeoff angle. (e) for comparison, determine the hang time of a whitetail deer making a jump with center-of-mass elevations yi = 1.20 m, ymax = 2.45 m, and yf = 0.750 m.