Results 1 to 3 of 3

Math Help - [SOLVED] Calculating units of speed / error?

  1. #1
    Member
    Joined
    Jun 2009
    Posts
    86

    [SOLVED] Calculating units of speed / error?

    An avalanche sliding down a mountain has a constant acceleration of 3.0m/s^2 [W]. It takes 6.0s to cover a displacement off 78m[W].

    a) Calculate its initial velocity.

    G:

    Acceleration = 3.0m/s^2
    Time = 6.0s
    Displacement = 78m [W]

    R:

    Velocity1

    A:

    d = v1(t) + 1/2a(t)^2
    ...Isolating Variable...
    (2d - a(t)^2) / 2t = v1

    S:

    (2(78m[W]) - 3.0m/s^2[W](6.0s)^2) / 2(6.0s) = v1
    (156m[W] - 3.0m/s^2[W](36s)) / 12s = v1
    (156m[W] - 108m/s^3[W]) / 12s = v1

    This is the problem I'm having. I am not able to subtract the different units of speed. My textbook says that the answer to this question is 4.0m/s[W]. If I were to subtract 108 from 156 and divide by 12, I would get 4.0 correct, but no correct units/direction. Where was my error here? I usually get a little confused when I divide s^2 by s or something similar.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Jun 2009
    Posts
    86
    (156m[W] - 108m/s[W]) / 12s = v1

    Figured out that the 108m/s should not have been cubed... but I still can't subtract a m/s from m.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Jun 2009
    Posts
    86
    Nvm, found the mistake with the 36s^2. Problem solved.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Calculating the error in an estimate of <x^2>
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: December 5th 2011, 02:33 PM
  2. Relative Error and Units in last place (ulps)
    Posted in the Advanced Math Topics Forum
    Replies: 0
    Last Post: December 16th 2010, 07:52 AM
  3. Calculating type 2 error?
    Posted in the Statistics Forum
    Replies: 0
    Last Post: March 6th 2010, 12:47 PM
  4. Calculating speed.
    Posted in the Math Topics Forum
    Replies: 3
    Last Post: February 12th 2010, 05:27 PM
  5. Calculating probability of tye 1 error
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: February 13th 2009, 04:55 AM

Search Tags


/mathhelpforum @mathhelpforum