Experimental determination of the drag coefficient: When retardation due to air resistance is proportional to downward velocity V , in feet per second, falling objects obey the equation of change
where r is known as the drag coefficient. One way to measure the drag coefficient is to measure and record terminal velocity.
a. We know that an average-size man has a terminal velocity of 176 feet per second. Use this to show that the value of the drag coefficient is r = 0.1818 per second. (Hint: To say that the terminal velocity is 176 feet per second means that when the velocity V is 176, velocity will not change. That is, dV dt = 0. Put these bits of information into the equation of change and solve for r.)
b. An ordinary coffee filter has a terminal velocity of about 4 feet per second. What is the drag coefficient for a coffee filter?
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