# Real World EXAMPLES of Exponential and Logarithmic Functions

by sillydude
Tags: examples, exponential, functions, logarithmic, real, world
 P: 21 Hey, is there anyone who can provide 2 graphical examples of either logarithmic or exponential functions relating to the real world. I've looked in many places and have given up. Please help. Thanks in advance
 P: 1,757 http://en.wikipedia.org/wiki/Exponential_growth google for logarithmic on your own, one could be for biology/chemistry
 Mentor P: 37,632
HW Helper
P: 2,692

## Real World EXAMPLES of Exponential and Logarithmic Functions

Financial investments, bacterial growth rates and population sizes. These are not really specific examples - only general applications which you can also find in some textbooks. Slightly more specific application is savings bonds.
 PF Patron P: 1,816 The amount of a radioactive element remaining as a function of time. (negative exponential A(t) = A(0)*e^-kt). Similarly the amount of a chemical substance left as function of time when it reacts according to a 'first order' rate law -d[A]/dt = k[A] in many simple reactions. The amount of water left in a cylinder emptying as function of time if rate proportional to pressureThe charge left on a capacitor discharging without inductance as function of time. The density of gas under constant gravity as function of height . The rate of elementary chemical reaction as function of temperature. All negative exponentials some of them reflection fundamental physics (Maxwell distribution).
 P: 4 yessir. I can. My example is in the form of a word problem about Newton's Law of Cooling. Its an example for modeling with Exponential and Logarithmic Equations: Use Newton's Lay of Cooling, T = C + (T0 - C)e-kt, to solve this exercise. At 9:00 A.M., a coroner arrived at the home of a person who had died during the night. The temperature of the room was 70 degrees F, and at the time of death the person had a body temperature of 98.6 degrees F. The coroner took the body's temperature at 9:30 A.M., at which time it was 85.6 degrees F, and again at 10:00 A.M., when it was 82.7 degrees F. At what time did the person die?????? T = C + (T0 - C)e-kt If you do not know what the variable's mean...these are their meanings: T = temperature of a heated object C = constant temperature of the surrounding medium (the ambient temp) T0 = initial temperature of the heated object k = negative constant associated with the cooling object t = time (in minutes)

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