Notices
Results 1 to 4 of 4

Thread: laws of mechanics

  1. #1 laws of mechanics 
    Forum Freshman
    Join Date
    Nov 2007
    Location
    Washington State
    Posts
    77
    I'm currently reading six not so easy pieces. It tells me in previous chapters we have seen that the laws of mechanics can be summarized by a set of three equations:

    m(d^(2)x/dt^(2))= Fx but the x is a little subscript

    The other two equations are the same but with a y substituted for x in one and a Z in the other.

    Can anyone explain to me the variables because I have never seen this equation before and the book assumes I have. The funny part is the "previous chapters" part because this is located in the first chapter.


    Reply With Quote  
     

  2.  
     

  3. #2  
    Suspended
    Join Date
    Apr 2007
    Location
    Pennsylvania
    Posts
    8,795
    The first equation is simply a statement of Newton's law, Force = mass * acceleration. More specifically the component of force along the "x" axis is equal to mass multiplied by the second derivative of position x with respect to time. (The first derivative is velocity, the second derivative is acceleration). The other two equations relate the y and z component of force to the acceleration in those directions.


    Reply With Quote  
     

  4. #3  
    Forum Bachelors Degree
    Join Date
    May 2007
    Location
    NC USA
    Posts
    488
    *
    The equation you posted is in calculus notation. The symbol ^2 does not have the familiar meaning that some quantity is squared. It simply means that a particular mathematical operation has been repeated.

    Your chapter assumes that the reader has completed his first course in calculus. Readers who have indeed done so will be in familiar territory. To those who haven't, equations such as the one you have noted will be totally incomprehensible -- but familar enough to let the reader think he ought to be able to undertand.

    EV33, we don't know your curent educational level. If you have any more questions for us, let us know your background so we can offer a meaningful response.

    *
    Reply With Quote  
     

  5. #4  
    Forum Freshman
    Join Date
    Nov 2007
    Location
    Washington State
    Posts
    77
    Thanks guys that makes sense. I just finished my first semester in calculus this year, and the physics course I am taking is so basic that nothing is calculus based. When I see second derivative I am used to is f''. But yeah I am sure I will be back for help on something else another because that is only on the second page.

    Thank you
    Reply With Quote  
     

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