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!

Object Velocity Question help

  1. Jan 14, 2014 #1
    Hi was wondering if i could get some help with this question

    -An object is allowed to free fall from rest from a height of 9 m. What will be its velocity on striking the ground?

    ---My solution to this was to simply multiply the 9m by 9.81m/s... which is wrong the solution posted to this question is 13.29m/s.... which formula should be used for this question?

    Any help would be greatly appreciated thank you
  2. jcsd
  3. Jan 14, 2014 #2


    User Avatar
    Homework Helper
    Gold Member

    Hello bad at math gu,

    Welcome to Physics Forums!

    That would be sort of the right approach if you were to allow an object to fall from rest for 9 seconds, but not 9 meters. (and you forgot to square the seconds in your acceleration units: 9.81 m/s2)

    Find one of your kinematics equations for uniform acceleration that has initial and final velocity, acceleration and displacement (but not time). That's the easiest way to solve this problem. :smile:

    You can find such an equation here: https://www.physicsforums.com/showthread.php?t=110015
  4. Jan 14, 2014 #3
    HA got it thank you
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted