Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Help pleeeese (validity of f=ma, mass of diff.temp objects)

  1. Mar 15, 2005 #1
    help pleeeese~~ (validity of f=ma, mass of diff.temp objects)

    :cry: please help me~ desperate...

    1. is f=ma valid in all situations? explain your reasons~
    2. is the mass of a hot frying pan different from a cold frying pan? why?

    thank you~~~
  2. jcsd
  3. Mar 15, 2005 #2
    Newtons laws are obeyed only in inertial frames.In an accelarated frame they are not obeyed.
    For simplicity consider u are travelling in a trian with an accelaratin a. If u look a tree outside u will find that tree is also accelarating wrt u. But no force is acting on the tree. So F = ma is not valid.
  4. Mar 15, 2005 #3
    Consider the second question,

    When we saz E= mc2 we mean that mass and energy are two diff forms of same thing. U can say that frying pan has more energy or more mass than ordinary one.
  5. Mar 16, 2005 #4


    User Avatar
    Science Advisor

    kiwikiwi: I see you've asked a number of questions, all of which look like verbatim from a text book. Please read the sticky at the top of this homework forum.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook