What is the difference between radioactive decay and radioactivity?

Half life, population growth and decay, newton's law of cooling, continuous compounding interest help?

• An unknown radioactive element decays into non-radioactive substances. In 180 days the radioactivity of a sample decreases by 33 percent. (a) What is the half-life of the element? half-life (days): (b) How long will it take for a sample of 100 mg to decay to 69 mg? time needed (days): Newton's law of cooling states that the temperature of an object changes at a rate proportional to the difference between its temperature and that of its surroundings. Suppose that the temperature of a cup of coffee obeys Newton's law of cooling. If the coffee has a temperature of 195 degrees Fahrenheit when freshly poured, and 3 minutes later has cooled to 181 degrees in a room at 66 degrees, determine when the coffee reaches a temperature of 156 degrees. The coffee will reach a temperature of 156 degrees in _____ minutes. You have 600 dollars in your bank account. Suppose your money is compounded every month at a rate of 0.3 percent per month. (a) How much do you have after t years? y(t)=________ (function of t) (b) How much do you have after 110 months? y(110)=___________ if anyone could please help me! i would be extremely appreciative! and i'm desperate lol

• Answer:

  face this question is complicated but I do not know