R = log where log (A) A - the measure of the amplitude of the earthquake wave Ao the amplitude of the smallest detectable wave (or standard wave). An earthquake is measured with a wave amplitude 626 times as great as Ag. What is the magnitude of this earthquake using the Richter scale, to the nearest tenth? The earthquake registered on the Richter scale. The half-life of Radium-226 is 1590 years. If a sample contains 300 mg, how many mg will remain after 1000 years? The half-life of Palladium-100 is 4 days. After 20 days a sample of Palladium-100 has been reduced to a mass of 1 mg. What was the initial mass (in mg) of the sample? What is the mass 6 weeks after the start? At the beginning of an experiment, a scientist has 252 grams of radioactive goo. After 180 minutes, her sample has decayed to 3.9375 grams. What is the half-life of the goo in minutes? Find a formula for G(t), the amount of goo remaining at time t. G(t) How many grams of goo will remain after 29 minutes? A bacteria culture initially contains 1500 bacteria and doubles every half hour. Find the size of the baterial population after 80 minutes. Find the size of the baterial population after 5 hours. The doubling period of a bacterial population is 20 minutes. At time t = 80 minutes, the bacterial population was 90000. What was the initial population at time t = 0? Find the size of the bacterial population after 4 hours. An object with initial temperature 140F is submerged in large tank of water whose temperature is 70F. Find a formula for F(t), the temperature of the object after t minutes, if the cooling constant is k = 1.6 F(t)= A bank features a savings account that has an annual percentage rate of r = 5.4% with interest compounded quarterly. Mary Joy deposits $11,000 into the account. nt The account balance can be modeled by the exponential formula S(t) = P(1 + 77) ", where S is the future value, P is the present value, is the annual percentage rate written as a decimal, n is the number of times each year that the interest is compounded, and t is the time in years. (A) What values should be used for P, r, and n? P = 11000 T= 0.135 n = 4 (B) How much money will Mary Joy have in the account in 7 years? Answer = $