return to main page

Related Rates Worksheet 

For each related rates problem below, try to use the following strategies (found on pg. 267 of your text with slight changed for numbers 6 and 7):

1.      Read the problem carefully

2.      Draw a diagram if possible.

3.      Introduce notation.  Assign symbols to all quantities that are functions of time.

4.      Express the given information and the required rate in terms of derivatives.

5.      Write an equation that relates the various quantities of the problem.  If necessary, use the geometry of the situation to eliminate one of the variables by substitution.

6.      Use the Chain Rule to differentiate into the resulting equation.  (also, think implicit differentiation)

7.      Solve for the unknown rate.

 ***************************************************************************

The following problems are exercises from your textbook.

1.      Suppose oil spills from a ruptured tanker and spreads in a circular pattern.  If the radius of the oil spill increases at a constant rate of 1 m/s, how fast is the area of the spill increasing when the radius is 30m?

2.      A street light is mounted at the top of a 15-ft-tall pole.  A man 6ft tall walks away from the pole with a speed of 5ft/sec along a straight path.  How fast is the tip of his shadow moving when he is 40ft from the pole?

3.      A man starts walking north at 4ft/sec from a point P.  Five minutes later a woman starts walking south at a rate of 5ft/sec from a point 500 ft due east of P.  At what rate are the people moving apart 15 minutes after the woman starts walking?

4.      The altitude of a triangle is increasing at a rate of 1cm/min while the area of the triangle is increasing at a rate of 2cm2/min.  At what rate is the base of the triangle changing when the altitude is 10cm and the area is 100cm2?

5.      Water is leaking out of a conical tank at a rate of 10,000 cm3/min at the same time that water is being pumped into the tank at a constant rate.  The tank has height 6 m and the diameter at the top is 4 m.  If the water level is rising at a rate of 20cm/min when the height of the water is 2 m, find the rate at which water is being pumped into the tank.