What Is This Formula?

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  • cabinetman
    Gone but not Forgotten RIP
    • Jun 2006
    • 15216
    • So. Florida
    • Delta

    What Is This Formula?

    A buddy sent me this and told me to figure it out. I'm stumped.
    .

    .
  • bruce hylton
    Established Member
    • Dec 2008
    • 211
    • winlock, wa
    • Dewalt today

    #2
    I have no education in the field, so it must be electrical or Greek.

    Comment

    • jkristia
      Established Member
      • Jan 2006
      • 114
      • Simi Valley, CA

      #3
      google for 'a sin omega t' gives this hint

      The mathematical properties of a wave
      http://physics.about.com/od/mathemat...emechanics.htm

      Not sure if THAT is any help - I certainly do not understand it

      Comment

      • jziegler
        Veteran Member
        • Aug 2005
        • 1149
        • Salem, NJ, USA.
        • Ryobi BT3100

        #4
        With the picture of a spring there, it looks mechanical, not electrical to me. Looks like the oscillation of a mass (m) on an ideal spring with a spring constant of k. If I'm right, that a pretty common physics 1 type problem (been a few years). I'm not sure if that equation matches.

        Of course, that would be for an ideal, frictionless system in a vacuum, and with the mass being a point mass. The eqautions get messy as soon as you start adding any of those types of effects.

        Jim

        Comment

        • Wood_workur
          Veteran Member
          • Aug 2005
          • 1914
          • Ohio
          • Ryobi bt3100-1

          #5
          That is the physics equation for the position of a oscillating spring at a time t. A is the amplitude, omega has to do with the starting position (the phasor), k is the spring constant, m is the mass at the end of the spring, and t is the time.
          Alex

          Comment

          • Uncle Cracker
            The Full Monte
            • May 2007
            • 7091
            • Sunshine State
            • BT3000

            #6
            Looks like a harmonic oscillation formula, but I don't recognize the application. Maybe earthquakes, ocean waves or ping-pong balls bouncing in a vacuum.

            Comment

            • LCHIEN
              Internet Fact Checker
              • Dec 2002
              • 21073
              • Katy, TX, USA.
              • BT3000 vintage 1999

              #7
              equation for oscillation of the spring and weight. Y is the vertical position of the mass and wt is the frequency in radians per second and t is time. A is the initial height.
              K is the spring constant (in something like cm/kg) and m is the mass in somthing like kg. Everyone here i assume knows how to convert radians per second to Hertz or revolutions per minute???

              it's an ideal equation as its not damped by any friction terms and will oscillate forever as you can tell by looking.
              Last edited by LCHIEN; 08-26-2009, 03:02 PM.
              Loring in Katy, TX USA
              If your only tool is a hammer, you tend to treat all problems as if they were nails.
              BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

              Comment

              • TB Roye
                Veteran Member
                • Jan 2004
                • 2969
                • Sacramento, CA, USA.
                • BT3100

                #8
                Ok, now what ? Way behond me

                Tom

                Comment

                • Wood_workur
                  Veteran Member
                  • Aug 2005
                  • 1914
                  • Ohio
                  • Ryobi bt3100-1

                  #9
                  Originally posted by LCHIEN
                  equation for oscillation of the spring and weight. Y is the vertical position of the mass and wt is the frequency in radians per second and t is time. A is the initial height.
                  K is the spring constant (in something like cm/kg) and m is the mass in somthing like kg. Everyone here i assume knows how to convert radians per second to Hertz or revolutions per minute???

                  it's an ideal equation as its not damped by any friction terms and will oscillate forever as you can tell by looking.
                  I'm thinking this is the amplitude because it is multiplying the entire equation (which would provide the height if the amplitude was NOT 1), and the initial position would be added to the omega*t. I think this equation assumes an initial position of 0.

                  Also, I believe that the spring constant is generally given as force/distance, such as kg/cm. Otherwise this equation would out to have the square root of cm/kg^2.
                  Alex

                  Comment

                  • jziegler
                    Veteran Member
                    • Aug 2005
                    • 1149
                    • Salem, NJ, USA.
                    • Ryobi BT3100

                    #10
                    Originally posted by Wood_workur
                    I'm thinking this is the amplitude because it is multiplying the entire equation (which would provide the height if the amplitude was NOT 1), and the initial position would be added to the omega*t. I think this equation assumes an initial position of 0.

                    Also, I believe that the spring constant is generally given as force/distance, such as kg/cm. Otherwise this equation would out to have the square root of cm/kg^2.

                    In this case, amplitude and initial position are the same. sin(0) = 1. You would release at t=0 from position A

                    Jim

                    Comment

                    • Wood_workur
                      Veteran Member
                      • Aug 2005
                      • 1914
                      • Ohio
                      • Ryobi bt3100-1

                      #11
                      Originally posted by jziegler
                      In this case, amplitude and initial position are the same. sin(0) = 1. You would release at t=0 from position A

                      Jim
                      Sin(0) is 0. Cos(0) is 1.
                      Alex

                      Comment

                      • radhak
                        Veteran Member
                        • Apr 2006
                        • 3061
                        • Miramar, FL
                        • Right Tilt 3HP Unisaw

                        #12
                        My 10 year old chimes in : it's a formula for fun.

                        If you jump on 'y' with your skateboard it sproiinnngs you onto A and then you go wheeee onto the bottom of the pit and by then you would have gained enough momentum (ok, that's my word) to go all the way up to the next ramp and if you can manage to go over it you could complete it before you run out of time.

                        It is the mark of an educated mind to be able to entertain a thought without accepting it.
                        - Aristotle

                        Comment

                        • JR
                          The Full Monte
                          • Feb 2004
                          • 5633
                          • Eugene, OR
                          • BT3000

                          #13
                          Originally posted by radhak
                          My 10 year old chimes in : it's a formula for fun.
                          I am totally buying it, Dude!

                          JR
                          JR

                          Comment

                          • Mr__Bill
                            Veteran Member
                            • May 2007
                            • 2096
                            • Tacoma, WA
                            • BT3000

                            #14
                            It explains why the work expands to fill the time allowed.





                            Bill

                            Comment

                            • Sid
                              Established Member
                              • Apr 2004
                              • 139
                              • Bloomington, IL, USA.
                              • Craftsman 22124

                              #15
                              I recognize the formula from my physics major classes (MANY years ago) but the last time I saw it was in an e-mail, which I wouldn't be allowed to reproduce here, where it purported to mathematically describe a video of the harmonic motion of certain jiggly body parts.

                              Might that be where you saw it, C'man?

                              Sid

                              Comment

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