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: Free Fall

  1. Sep 25, 2007 #1
    1. The problem statement, all variables and given/known data

    Two ball are dropped from 5m high, Use 10 m/s^2 for the magnitude of the acceleration due to gravity.


    2. Relevant equations

    How do i start?

    3. The attempt at a solution

    not sure on how to start so i havent attempted:(
     
  2. jcsd
  3. Sep 25, 2007 #2

    Astronuc

    User Avatar
    Staff Emeritus
    Science Advisor

  4. Sep 25, 2007 #3
    the problem asks how much time is elapsed during the fall of the 5.0m at a rate of 10m/s^2

    Im sure there is an equation for this but i dont know which one or where to find it...
     
    Last edited: Sep 25, 2007
  5. Sep 25, 2007 #4

    Astronuc

    User Avatar
    Staff Emeritus
    Science Advisor

    If something starts at rest, i.e. with zero velocity, how far does is travel in time, t, if the acceleration is constant.

    See - http://hyperphysics.phy-astr.gsu.edu/hbase/acons.html

    The same concept applies for horizontal (x) or vertical (y) motion, provided the acceleration is constant.
     
  6. Sep 25, 2007 #5
    so... y=1/2at^2... y equal to the hight of 5m? if so then i get 5m=1/2(10m/s^2)T^2 which = square root of 5.00s which = 2.24s??? but the that answer is still wrong. What did i do wrong.
     
  7. Sep 25, 2007 #6
    o nvm should be the square root of 1.00s.... ill try that, wow i feel like an idiot... i need to sleep
     
  8. Sep 25, 2007 #7

    Astronuc

    User Avatar
    Staff Emeritus
    Science Advisor

    Well - you figured it out. Do get some sleep, and refer to hyperphysics when the mind is more relaxed.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook