1. Not finding help here? Sign up for a free 30min 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!

Unknown Speed

  1. Dec 14, 2006 #1
    Unknown Speed!!

    Hi all, I've got this problem in my physics class I can't figure it out. Iv'e changed the values because I only wan't to know How we can solve this..

    Here it goes:

    I have a 400 g (3,29 N) Meteor that crashed in the earth surface and reach a depth of 1.7 m . The scientist say that the ground had a resistance force of 1,0 x 10^6 N.

    (We ignore the air's friction.)

    What was the meteor's speed?


    It's all I've got.

    Iv'e done a graphic on paper whit vectors But I don't quite get the methos of doing it.

    Else.. I tried Caluculating the potiential energy (Ep = mgh) but I don't have the height.. Neither de speed for the Kinetic energy (Ek = 1/2 m v^2)

    Bah.. Help me out! :P:P
     
  2. jcsd
  3. Dec 14, 2006 #2

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Do you understand the relationship between force, distance, and work?

    W = F*d

    - Warren
     
  4. Dec 14, 2006 #3
    OHHH !! nevermind.. I get it!I will start working on it.
     
  5. Dec 14, 2006 #4
    Here is what I have done:

    W= Fr * Delta Sr
    W= 1000000 N * 1,7 m
    W= 1700000 J

    Ek = 1/2 * m * v^2
    1700000 j = 0.5 * 3,29 N * v^2
    1033434,65 j = v^2
    1016,58 m/s = V

    Meteor's speed is 1016,58 m/s
     
  6. Dec 14, 2006 #5

    chroot

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Be careful with your units. Mass should be in kilograms, not in newtons. Otherwise, yes, you have the right idea.

    - Warren
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?