Homework Help: Integral Areas and Physics Application

1. Jul 21, 2007

rhymes116

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. Jul 22, 2007

GoldPheonix

This should go in homework, dude.

3. Jul 23, 2007

mjsd

rhymes116

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.

4. Jul 23, 2007

Gib Z

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...

5. Jul 27, 2007

rhymes116

oops, sorry. Im new to this place. I figured it out anyways. Thanks for the heads up.

6. Jul 28, 2007

HallsofIvy

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!