Free Shipping on All Orders 1-866-764-1801

Vist our Online Store
+ Reply to Thread
Results 1 to 16 of 16
  1. #1

    Member Sales Rating: (4)

    Join Date
    Feb 2007
    Posts
    6,974

    Default Physics Question

    Hi,

    Was wondering if anyone here would know how to solve the following problem:

    "A swimming pool measures a length of 5.80m, width 4.30m, and depth 3.20m. Compute the force exerted by the water against the bottom. Do not include the force due to air pressure. Take the free fall acceleration to be g= 9.80m/s^2 , and the density of water to be 1000kg/m^3. Also compute the force exerted by the water against either end. Do not include the force due to air pressure."

    Any help would be greatly appreciated.

    Thanks in advance!

    P.S. This is for my "fluid mechanics" course.
    polkaudio RT35 Bookshelves
    polkaudio 255c-RT Inwalls
    polkaudio DSWPro550WI
    polkaudio XRT12 XM Tuner
    polkaudio RM6750 5.1

    Front projection, 2 channel, car audio... life is good!

  2. #2

    Member Sales Rating: (28)

    Join Date
    Mar 2005
    Location
    Right here.
    Posts
    10,414

    Default

    After 25 years or so I forgot all the formulas, but this seems a pretty basic thing....don't you have your book?? ;)
    _________________________________________________
    ***\\\\\........................... My Audio Journey ............................./////***

    2008 & 2010 Football Pool WINNER
    SOPA

    Thank God for different opinions. Imagine the world if we all wanted the same woman

  3. #3

    Member Sales Rating: (28)

    Join Date
    Mar 2005
    Location
    Powder Springs, GA
    Posts
    5,293

    Default

    Isn't that why you are in school? You tell us!

  4. #4

    Member Sales Rating: (4)

    Join Date
    Feb 2007
    Posts
    6,974

    Default

    Quote Originally Posted by HTrookie View Post
    After 25 years or so I forgot all the formulas, but this seems a pretty basic thing....don't you have your book?? ;)
    I thought it was a basic question, but it doesn't appear to be. Spent hours yesterday trying to figure it out with a friend, to no avail. It's also labeled a "Challenge Problem" in the textbook.
    polkaudio RT35 Bookshelves
    polkaudio 255c-RT Inwalls
    polkaudio DSWPro550WI
    polkaudio XRT12 XM Tuner
    polkaudio RM6750 5.1

    Front projection, 2 channel, car audio... life is good!

  5. #5

    Member Sales Rating: (14)

    Join Date
    Jun 2004
    Location
    Live Free or Die
    Posts
    10,965

    Default

    I'm guessing you can't use the basic F=ma for this one?

    Force = mass * acceleration
    (where Mass = volume * density)

    Seems a bit too simple that way...
    If you will it, dude, it is no dream.

  6. #6

    Member Sales Rating: (4)

    Join Date
    Feb 2007
    Posts
    6,974

    Default

    I agree, seems WAY too simple that way...and the fact that it is a challenge problem. The professor said he would give 5pts extra credit for solving the question.
    polkaudio RT35 Bookshelves
    polkaudio 255c-RT Inwalls
    polkaudio DSWPro550WI
    polkaudio XRT12 XM Tuner
    polkaudio RM6750 5.1

    Front projection, 2 channel, car audio... life is good!

  7. #7

    Member Sales Rating: (1)

    Join Date
    Jul 2003
    Location
    York, PA / Mumbai, India
    Posts
    4,474

    Default

    Looks really straight forward to me....
    5.8*4.3*3.2=79.81 M^3*1,000Kg/M^3=79,810 Kg*9.8N/Kg= 782,000 N or 782 kN
    (3 sig figs as given)

    Did you write the whole question?

    Oh snap, I got it!!! Haha! That's just the pressure on the bottom, you need to calculate the pressure on the sides of the pool as well! Or I should say only on the sides... The wording is hard, not the problem...
    Last edited by jdhdiggs; 09-18-2007 at 10:44 AM.
    There is no genuine justice in any scheme of feeding and coddling the loafer whose only ponderable energies are devoted wholly to reproduction. Nine-tenths of the rights he bellows for are really privileges and he does nothing to deserve them. We not only acquired a vast population of morons, we have inculcated all morons, old or young, with the doctrine that the decent and industrious people of the country are bound to support them for all time.-Menkin

  8. #8

    Member Sales Rating: (14)

    Join Date
    Jun 2004
    Location
    Live Free or Die
    Posts
    10,965

    Default

    Ohhh, I missed the part whree it said compute the force on either end. I think what jdhdiggs said is true for the bottom though. No idea how to do the sides; I haven't taken physics in almost 10 years.
    If you will it, dude, it is no dream.

  9. #9

    Member Sales Rating: (9)

    Join Date
    Sep 2006
    Location
    Baltimore
    Posts
    2,487

    Default

    Cool. I feel better now. I came up with the force on the bottom just like jdhdiggs, the force on the sides seemed a bit trickier.
    Wris****ch--->Crisco

  10. #10

    Member Sales Rating: (28)

    Join Date
    Mar 2005
    Location
    Powder Springs, GA
    Posts
    5,293

    Default

    You'll need to dig into your Calculus to get the force on the sides.

  11. #11

    Member Sales Rating: (1)

    Join Date
    Jul 2003
    Location
    York, PA / Mumbai, India
    Posts
    4,474

    Default

    Sides are easy, I just suck at metric. Pressure is just a linear function of depth and you just integrate it across the sides (Simple calc 1, hell trig works too)

    IIRC (LOOK THESE UP!!!)
    Roughly 9800 N/M^2 of depth Pressure at the bottom is 31,360 N/M^2, at the top it's 0 N/M^2. (Think triangles) Pressure on narrow end would be 67.4 kN and the long sides would be 90.9 kN. That's each side. So total pressure: 1,100 kN (1,098.854 kN before sig figs)
    Last edited by jdhdiggs; 09-18-2007 at 10:59 AM.
    There is no genuine justice in any scheme of feeding and coddling the loafer whose only ponderable energies are devoted wholly to reproduction. Nine-tenths of the rights he bellows for are really privileges and he does nothing to deserve them. We not only acquired a vast population of morons, we have inculcated all morons, old or young, with the doctrine that the decent and industrious people of the country are bound to support them for all time.-Menkin

  12. #12

    Member Sales Rating: (6)

    Join Date
    Dec 2003
    Location
    NC/AR
    Posts
    11,295

    Default

    Ahhh, I remember problems like these. But integration was definitely Calc 2 for us, not Calc 1.

    But, alas, I've forgotten every bit of it.
    Quote Originally Posted by George Grand View Post
    Quote Originally Posted by Jstas View Post
    Simple question. If you had a cool million bucks, what would you do with it?
    Wonder WTF happened to the rest of my money.
    My Saga
    Equipment Pictures

    [2CH]
    Rotel RCD-02
    Yamaha KX-W900U
    Sony ST-S500ES
    Denon DP-7F
    Parasound P/HP-850
    Parasound HCA-1000A
    Klipsch RF-35


    [In Storage]
    Yamaha CDR-HD1300
    ASL Wave 20 monoblocks
    Pro-Ject Phono Box MKII


    [Car System]
    Pioneer Premier DEH-P860MP
    Memphis 16-MCA3004
    Boston Acoustic RC520

  13. #13

    Member Sales Rating: (1)

    Join Date
    Jul 2003
    Location
    York, PA / Mumbai, India
    Posts
    4,474

    Default

    It's not really a calculas problem, it's trig 1. 1/2B*H then multply it be the length of the side and you're golden.
    There is no genuine justice in any scheme of feeding and coddling the loafer whose only ponderable energies are devoted wholly to reproduction. Nine-tenths of the rights he bellows for are really privileges and he does nothing to deserve them. We not only acquired a vast population of morons, we have inculcated all morons, old or young, with the doctrine that the decent and industrious people of the country are bound to support them for all time.-Menkin

  14. #14

    Member Sales Rating: (4)

    Join Date
    Feb 2007
    Posts
    6,974

    Default

    Quote Originally Posted by audiobliss View Post
    Ahhh, I remember problems like these. But integration was definitely Calc 2 for us, not Calc 1.

    But, alas, I've forgotten every bit of it.
    Same here, did integration in HS but forgot a lot of it now that I'm in college.
    polkaudio RT35 Bookshelves
    polkaudio 255c-RT Inwalls
    polkaudio DSWPro550WI
    polkaudio XRT12 XM Tuner
    polkaudio RM6750 5.1

    Front projection, 2 channel, car audio... life is good!

  15. #15

    Member Sales Rating: (4)

    Join Date
    Feb 2007
    Posts
    6,974

    Default

    Quote Originally Posted by jdhdiggs View Post
    Sides are easy, I just suck at metric. Pressure is just a linear function of depth and you just integrate it across the sides (Simple calc 1, hell trig works too)

    IIRC (LOOK THESE UP!!!)
    Roughly 9800 N/M^2 of depth Pressure at the bottom is 31,360 N/M^2, at the top it's 0 N/M^2. (Think triangles) Pressure on narrow end would be 67.4 kN and the long sides would be 90.9 kN. That's each side. So total pressure: 1,100 kN (1,098.854 kN before sig figs)
    Thanks for your help!
    polkaudio RT35 Bookshelves
    polkaudio 255c-RT Inwalls
    polkaudio DSWPro550WI
    polkaudio XRT12 XM Tuner
    polkaudio RM6750 5.1

    Front projection, 2 channel, car audio... life is good!

  16. #16

    Member Sales Rating: (1)

    Join Date
    Jul 2003
    Location
    York, PA / Mumbai, India
    Posts
    4,474

    Default

    Oh, and if I'm wrong its because I haven't even looked at that stuff for 11+ years... Good luck! ;)
    There is no genuine justice in any scheme of feeding and coddling the loafer whose only ponderable energies are devoted wholly to reproduction. Nine-tenths of the rights he bellows for are really privileges and he does nothing to deserve them. We not only acquired a vast population of morons, we have inculcated all morons, old or young, with the doctrine that the decent and industrious people of the country are bound to support them for all time.-Menkin

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

     

Similar Threads

  1. Physics riddle
    By petrym in forum The Clubhouse
    Replies: 14
    Last Post: 08-26-2006, 04:54 PM
  2. Physics question
    By audiobliss in forum The Clubhouse
    Replies: 39
    Last Post: 11-07-2005, 10:15 PM
  3. Very cool physics demo!
    By Mazeroth in forum The Clubhouse
    Replies: 4
    Last Post: 08-19-2005, 09:06 AM
  4. Genesis Physics Model 11 Version II
    By kingtut in forum Speakers
    Replies: 6
    Last Post: 08-16-2005, 11:04 AM
  5. Physics that led to damage 6510
    By sirogenous in forum Car Audio & Electronics
    Replies: 1
    Last Post: 07-17-2001, 10:33 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts