Frank's automobile engine runs at 100°C. On a day when the outside temperature is 10°C, he turns off the ignition and notes that five minutes later, the engine has cooled to 75°C. When will the engine cool to 40°C? (Round your answer to two decimal places.) minutes after the ignition was turned off Use Newton's Law of Cooling. A cold metal bar at -50°C is submerged in a pool maintained at a temperature of 60°C. After 45 seconds, the temperature of the bar is 20°C. How long will it take for the bar to attain a temperature of 30°C? (Round your answer to two decimal places.) X seconds after submersion An aquarium pool has volume 2 106 liters. The pool initially contains pure fresh water. At t = 0 minutes, water containing 10 grams/liter of salt is poured into the pool at a rate of 100 liters/minute. The salt water instantly mixes with the fresh water, and the excess mixture is drained out of the pool at the same rate (100 liters/minute). (a) Write a differential equation for S(t), the mass of salt in the pool at time t. ds = dt X (b) Solve the differential equation to find S(t). s(t) = (c) What happens to S(t) as t → co? S(t)→ 20000000 grams