1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Integral Areas and Physics Application

  1. Jul 21, 2007 #1
    Greetings everyone! I am new to this forum. I take a variety of
    mathematic courses and needed some help so found this website. Its
    great to see a variety of people interested in mathematics!

    In my current calculus class, we are learning about Integral areas in
    geometric shapes and application in physics. Here are a few problems
    practice problems that I had trouble with. If anyone can solve them
    (you can put the last definite integral formula to be solved) with an
    explanation, I'd appreciate that!

    1.) A dam is approximatly shaped like a trapezoid with height 726
    feet, width at top of 1244 ft and width at base of 660 ft. Determine
    total force on dam if the water is 700ft deep. (Water weighs about
    62.4 lb/feet cubed.)

    2.) A rectangular pool measures 10 feet deep, 15 feet wide, and 40
    feet long. It is filled with pure water to 6 inches below the top. If
    a one horsepower motor can perform 550 ft*lbs of work per second, then
    what size motor is required to empty the pool in 1 hour? The weight
    density of pure water is about 62.4 lbs per cubic feet.

    3.) Soot produced by a garbage incinerator spread out in a circular
    pattern. The depth, H(r) (in mm) of the soot deposited each month at a
    distance r kilometers from the incinerator is gvien by H(r)=
    0.23e^-2r. Determine the volume of soot in meters cubed, deposited
    within a 5km radius of the incinerator.

    4.) Cables connecting the towers of the George Washignton Bridge are
    approximated by the parabola: y=0.00013x^2 ft, where x is the
    horizontal distance from the vertex of the cable. If the distance
    between the two towers is 3500 feet, then determine the exact length
    of the cable that spans them. Also give the 4 sign. fig approximation.
  2. jcsd
  3. Jul 22, 2007 #2
    This should go in homework, dude.
  4. Jul 23, 2007 #3


    User Avatar
    Homework Helper


    you will have to be clear and show us what you are having problems in regards to those problems. merely posting them like that, it is not very helpful for anybody.
  5. Jul 23, 2007 #4

    Gib Z

    User Avatar
    Homework Helper

    Perhaps he purposely posted in this thread knowing that he would also post in the appropriate one in the homework section, just to add to his post count! Who would do such a thing...
  6. Jul 27, 2007 #5
    oops, sorry. Im new to this place. I figured it out anyways. Thanks for the heads up.
  7. Jul 28, 2007 #6


    User Avatar
    Science Advisor

    You were expected to read the forum rules before you started posting!

    Homework problems go in the homework section and you must show what you have already tried on the problem- just posting the problems themselves will get you a lot of "nasty" responses!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook