Concept explainers
25–28 ■ Law of Cooling These exercises use Newton’s Law of Cooling.
Time of Death Newton’s Law of Cooling is used in homicide investigations to determine the time of death. The normal body temperature is
(a) Find a function
(b) If the temperature of the body is now
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Algebra and Trigonometry (MindTap Course List)
- A bottle of soda with a temperature of 71 Fahrenheit was taken off a shelf and placed ina refrigerator with an internal temperature of 35 .After ten minutes, the internal temperature of thesoda was 63F . Use Newton’s Law of cooling towrite a formula that models this situation. To thenearest degree, what will the temperature of thesoda be after one hour?arrow_forwardThe Beer-Lambert Law As sunlight passes through the waters of lakes and oceans, the light is absorbed, and the deeper it penetrates, the more its intensity diminishes. The light intensity I at depth x is given by the Beer-Lambert Law: I=I0ekx where I0 is the light intensity at the surface and k is a constant that depends on the murkiness of the water see page 402. A biologist uses a photometer to investigate light penetration in a northern lake, obtaining the data in the table. Light intensity decreases exponentially with depth. Use a graphing calculator to find an exponential function of the form given by the Beer-Lambert Law to model these data. What is the light intensity I0 at the surface on this day, and what is the murkiness constant k for this lake? Hint: If your calculator gives you a function of the form I=abx, convert this to the form you want using the identities bx=eln(bx)=exlnb. See Example 1b. Make a scatter plot of the data, and graph the function that you found in part a on your scatter plot. If the light intensity drops below 0.15 lumen lm, a certain species of algae cant survive because photosynthesis is impossible. Use your model from part a to determine the depth below which there is insufficient light to support this algae. Depth ft Light intensity lm Depth ft Light intensity lm 5 10 15 20 13.0 7.6 4.5 2.7 25 30 35 40 1.8 1.1 0.5 0.3arrow_forwardThe Beer-Lambert Law As sunlight passes through the waters of lakes and oceans, thelight isabsorbed, and the deeper it penetrates, the more its intensity diminishes. The light intensityI at depth x is given by the Beer-Lambert Law: I=I0ekx Where I0 the light intensity at the surface and k isis a constant that depends on the murkiness of the water (see page 402). A biologist uses a photometer to investigate light penetration in a northern lake, obtaining the data in the table. (a) Use a graphing calculator to find an exponential function of the form given by the Beer-Lambert Law to model these data. What is the light intensity I0 at the surface on this day, and what is the “murkiness” constant kfor this lake?(Hint: if your calculator gives you a function of the form I=abx .convert this to the form you want using the identities bx=eIn(bx)=exInb . See Example 1(b).) (b) Make a scatter plot of the data, and graph the function that you found in part (a) on your scatter plot. (c) If the intensity drops below 0.15 lumen (lm) , a certain species of algae can’t survive because photosynthesis is impossible. Use your model from part (a) to determine the depth below which there is insufficient light to support this algae.arrow_forward
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