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: Force Diagram

  1. Mar 10, 2010 #1
    1. The problem statement, all variables and given/known data
    I have to draw a force diagram for a rock dropped off a cliff at the moment of release.
    Is there any force acting upward on the rock at the moment of release?


    2. Relevant equations
    none


    3. The attempt at a solution
    I know the force of gravity acts downward on the rock. My thinking is that the only force acting on the rock at the moment of release is gravity downward, then as it falls there is air resistance upward and a greater force of gravity downward. When a rock hits it's terminal velocity however the forces of gravity and air resistance are equal. Is this correct?
     
  2. jcsd
  3. Mar 10, 2010 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi cheerspens! :smile:
    Equal and opposite! :biggrin:

    Otherwise, completely correct! :smile:

    (i assume you're supposed to ignore the atmospheric pressure all round the rock :wink:)
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook