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?

Atank holds 1000 gallons of water, which drains from the bottom of the tank in half an hour. the values in the table show the volume v of water remaining in the tank (in gallons) after t minutes.t(min) 5 10 15 20 25 30v(gal) 694 444 250 111 28 0(a) if p is the point (15, 250) on the graph of v, find the slopes of the secant lines pq when q is the point on the graph with t = 5, 10, 20, 25, and 30.(b) estimate the slope of the tangent line at p by averaging the slopes of two secant lines.(c) use a graph of the function to estimate the slope of the tangent line at p. (this slope represents the rate at which the water is flowing from the tank after 15 minutes.)show all steps.

What does the law of conservation of mass state?

Which are causes of mechanical weathering? (check all that apply) a. acid rain b. plant growth c. animal actions d. carbon dioxide e. pressure release i chose b & e and got the question wrong.