a) A stone is thrown vertically upward from the ground with an initial velocity of 40 ft/s. How high will the stone go?

b) A population of 200 kangaroos is released into the forest. During the first three years, the population increases to 500 kangaroos. Assuming a logistic growth with a carrying capacity of 3000 kangaroos, predict the population after 8 years.

c) The rate of decay of radium is proportional to the amount present at any time. The half-life of radium is 1690 years and 20 mg of radium is present now. How much radium will remain after 1690 years?