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Physics 211, Quiz 1

Question 1:

The depth of the ocean is sometimes measured in fathoms: 1 fathom = 6 feet. Distance on the surface of the ocean is often measured in nautical miles: 1 nautical mile = 6076 feet.

One particular portion of the ocean is a rectangle 1.20 nautical miles by 2.60 nautical miles. It has a depth of 16 fathoms.

What is the volume of water beneath this area? Express your answer in cubic feet.

  Answer:   volume = (area on top) * (depth)

          Now, the area on top is 1.2 x 2.6 nautical miles, but we need
          to convert to feet:
                                         6076 feet
                  1.20 nautical miles * ----------- =  7,290 feet
                                        1 naut mile 

                                         6076 feet
                  2.60 nautical miles * ----------- = 15,800 feet
                                        1 naut mile 

          where I've kept only 3 significant digits in the number of feet,
          since there are only 3 significant digits in the number of 
          nautical miles.

          The depth of this region is

                                6 feet
                  16 fathoms * --------- =  96 feet
                                fathom


          So the volume of the region is


                  volume  =  (area on top)                  * (depth) 
 
                          =  (7,290 feet) * (15,800 feet) * (96 feet)

                          =  1.11 x 10^10  cubic feet 

Creative Commons License Copyright © Michael Richmond. This work is licensed under a Creative Commons License.