Notices
Results 1 to 4 of 4

Thread: light strings

  1. #1 light strings 
    Forum Freshman almirza's Avatar
    Join Date
    Nov 2005
    Location
    OMAN
    Posts
    80
    Hi

    Can any one tell me how the assumption of " light string " in dynamics questions make the tension in along the string the same???


    ALMIRZA
    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Professor river_rat's Avatar
    Join Date
    Jun 2006
    Location
    South Africa
    Posts
    1,497
    Well suppose the tension at two points along the string was different, you would have an unbalanced "internal" force acting on a massless piece of string which would result in tearing it apart as the acceleration would be infinite.


    As is often the case with technical subjects we are presented with an unfortunate choice: an explanation that is accurate but incomprehensible, or comprehensible but wrong.
    Reply With Quote  
     

  4. #3  
    Forum Freshman almirza's Avatar
    Join Date
    Nov 2005
    Location
    OMAN
    Posts
    80
    I am saying HOW this assumption will make it???

    Suppose a lorry pulls a car using a string so in some questions it says that this string is light , means does not have mass, and it is used in assuming that the tension on the lorry is the same on the car

    How assuming a massless string will make the tension on both vehicles the same???????
    ALMIRZA
    Reply With Quote  
     

  5. #4  
    Forum Professor river_rat's Avatar
    Join Date
    Jun 2006
    Location
    South Africa
    Posts
    1,497
    And i showed you how the assumption does - assume the contrary and arrive at a contradiction.
    As is often the case with technical subjects we are presented with an unfortunate choice: an explanation that is accurate but incomprehensible, or comprehensible but wrong.
    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
  •