Results 1 to 3 of 3

Math Help - vehicle stopping distances

  1. #1
    Junior Member
    Joined
    Apr 2007
    Posts
    38

    vehicle stopping distances

    I am given the speed in km/h (s) and total stopping distance in meters (t)
    Using the rule t = as^2 find values from 100 to 150.
    I looked in my pre-calc book and there is an equation for stopping distance which is d = v +(v^2/20) and this confused me. I did not get the same results, is it because it is in mpr and not kmr.
    Thank You,
    Keith
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Forum Admin topsquark's Avatar
    Joined
    Jan 2006
    From
    Wellsville, NY
    Posts
    10,211
    Thanks
    419
    Awards
    1
    Quote Originally Posted by keith View Post
    I am given the speed in km/h (s) and total stopping distance in meters (t)
    Using the rule t = as^2 find values from 100 to 150.
    I looked in my pre-calc book and there is an equation for stopping distance which is d = v +(v^2/20) and this confused me. I did not get the same results, is it because it is in mpr and not kmr.
    Thank You,
    Keith
    Whaaaaat?

    If you have an object undergoing constant acceleration (in the direction opposite to the velocity, ie a deceleration) and an initial velocity v0 then the stopping distance may be calculated as the position from the starting point where the velocity goes to 0. ie.
    0 = v0^2 + 2ad

    d = -v0^2/(2a)
    (The negative sign appears because I have tacitly assumed a positive direction as the direction of the initial velocity, and hence the acceleration, a, is negative.)

    Neither of the equations:
    t = as^2
    d = v +(v^2/20)
    come out in the correct units. I would treat them as highly suspect. (Or more likely as applications to specific problems.)

    -Dan
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Apr 2007
    Posts
    38

    vehicle stopping distances

    This question was one part of a problem in my math education class and it does not make any sense the way it is written.
    Thank You for looking it over. I will ask the professor when I get to class tonight.
    Thank you,
    Keith
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Control Vehicle vs. X Vehicle
    Posted in the Math Topics Forum
    Replies: 0
    Last Post: December 30th 2011, 01:26 PM
  2. Word Problem: A vehicle is traveling....
    Posted in the Algebra Forum
    Replies: 3
    Last Post: November 19th 2011, 04:09 PM
  3. [SOLVED] Vehicle Alignment Question
    Posted in the Math Topics Forum
    Replies: 2
    Last Post: September 23rd 2011, 07:05 PM
  4. Vehicle travelling question
    Posted in the Calculus Forum
    Replies: 3
    Last Post: May 27th 2009, 05:27 PM
  5. Estimating Speed of a Vehicle
    Posted in the Algebra Forum
    Replies: 4
    Last Post: October 19th 2008, 03:03 PM

Search Tags


/mathhelpforum @mathhelpforum