1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
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: Simple proportionality question

  1. Mar 20, 2012 #1
    Hey guys, simple question really:
    Given the equation
    Code (Text):
    v = (Gm/r)[SUP]1/2[/SUP]
    Is it wrong to say
    Code (Text):
    v is inversely proportional to r
    Or do you have to say
    Code (Text):
    v is inverslely proportional to r[SUP]1/2[/SUP]
     
  2. jcsd
  3. Mar 20, 2012 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    hey hmvince! :wink:
    yes!!! :smile:
    you don't have to say "inverslely"! o:)
     
  4. Mar 21, 2012 #3
    I thought you did have to, cos if you dont it means v increases with r, instead of v decreases with r.
    Do you mean to say this?:
    v is directly proportional to r-1/2?

    Looking at your number of posts and recognitions I dont mean to say you are wrong, just trying to figure it out for myself!
     
  5. Mar 21, 2012 #4

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    hi hmvince! :wink:

    yes, it's always best to ask until you're sure

    no point in losing even one mark in an exam by knowing the maths but not using the generally-accepted phrase! :smile:

    you can say

    v is proportional to r-1/2

    or

    v is inversely proportional to r1/2

    or

    v and r-1/2 are proportional

    or

    v and r1/2 are inversely proportional​

    (and you don't need "directly", since it adds no information … but it isn't actually wrong)
     
  6. Mar 21, 2012 #5
    Thankyou!
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook




Loading...
Similar Threads for Simple proportionality question Date
Spring, SHM Thursday at 12:50 PM
Simple closed force system -- Mechanics Apr 11, 2018
Simple stress problem Apr 7, 2018
Simple Harmonic Motion/Fundamental Frequency Apr 3, 2018
Show that the potential energy of a simple pendulum is proportional Apr 22, 2007