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Homework Help: Real World EXAMPLES of Exponential and Logarithmic Functions

  1. Jan 9, 2008 #1
    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
  2. jcsd
  3. Jan 9, 2008 #2
  4. Jan 9, 2008 #3


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  5. Jan 9, 2008 #4


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    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.
  6. Jan 9, 2008 #5


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    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).
    Last edited: Jan 9, 2008
  7. Apr 30, 2011 #6
    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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