Notices
Results 1 to 3 of 3

Thread: Can a magnetic fridge magnet stay on the fridge indefinitely?

  1. #1 Can a magnetic fridge magnet stay on the fridge indefinitely? 
    Junior Member
    Join Date
    May 2013
    Posts
    12
    I recently saw an unanswered "user question" in an old copy of the New Scientist which was supposed to be answered in the next edition. Unfortunately I don't have access to the next edition of the NS so I hope someone on this forum could answer it.
    A fridge magnet needs to overcome the force of gravity to stay where it is. It does this with magnetism (obviously). Here is the question: the fridge magnet needs to use energy to overcome the force of gravity. Does this therefore mean that the magnet will eventually run out of magnetic energy because it's used it all up? If the fridge magnet can stay on the fridge indefinitely, then it seems to have an indefinite supply of energy it can use just to maintain its position. Right?
    Reply With Quote  
     

  2. #2  
    Senior Member
    Join Date
    Oct 2013
    Location
    UK
    Posts
    997
    The magnet doesn't use need energy to stick to the fridge any more than a table needs energy to hold up things placed on it. It requires just a force. Energy is required to move a force though a distance. If it's not moving there is no distance and no energy required.
    Reply With Quote  
     

  3. #3  
    Senior Member
    Join Date
    Jan 2014
    Location
    out there
    Posts
    306
    You could ask the same question about paint falling off the wall and a car sinking through a concrete road.
    Reply With Quote  
     

Tags for this Thread

View Tag Cloud

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