Results 1 to 2 of 2

Math Help - Kinematic #1

  1. #1
    Junior Member
    Joined
    Oct 2008
    Posts
    68

    Kinematic #1

    Can someone please help me with this problem. I tried all day and couldnt get the correct answer. Thanks for your help!

    Question: While chasing Mitch for destroying his bike, Skid does the following to his Pinto: He starts from rest and accelerates at 0.6 m/s^2 for 15 sec. Travels at a constant velocity for 2 mins. Slows to a stop with an acceleration of -.75 m/s^2. What is the total distance Skid travels?

    What I did so far: v = v not + at
    = 0 + (.6)(15)
    = 9 m/s
    x = x not + v not t + 1/2 at^2
    = 9 (120s) = 1080 m
    v = v not = at
    -9 = -.75t
    t = 12 sec
    Then I plug 12 sec to the formula x = x not + v not t + 1/2 at^2 and got a weird number. I am really stuck. Thanks again for your help!
    Last edited by mr fantastic; October 5th 2009 at 03:22 AM. Reason: Re-titled post
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,621
    Thanks
    426
    Quote Originally Posted by jsu03 View Post
    Can someone please help me with this problem. I tried all day and couldnt get the correct answer. Thanks for your help!

    Question: While chasing Mitch for destroying his bike, Skid does the following to his Pinto: He starts from rest and accelerates at 0.6 m/s^2 for 15 sec. Travels at a constant velocity for 2 mins. Slows to a stop with an acceleration of -.75 m/s^2. What is the total distance Skid travels?
    break it up into 3 parts ... find the displacement for each part.

    \Delta x_1 = v_0 t + \frac{1}{2}at^2

    \Delta x_1 = 0 + \frac{1}{2}(0.6)(15^2)



    \Delta x_2 = vt = (v_0 + at_1)t_2

    \Delta x_2 = (0 + 0.6 \cdot 15)(120)



    \Delta x_3 = \frac{v_f^2 - v_0^2}{2a}

    \Delta x_3 = \frac{0 - 9^2}{2(-.75)}

    sum all three displacements.


    btw ... this isn't calculus. you should post problems like this in the "other topics" forum.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Two kinematic problems.
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: September 25th 2009, 03:12 PM
  2. Kinematic #2
    Posted in the Math Topics Forum
    Replies: 2
    Last Post: September 7th 2009, 05:20 PM
  3. Kinematic #3
    Posted in the Calculus Forum
    Replies: 2
    Last Post: September 6th 2009, 11:26 AM
  4. Physics Help-Kinematic Equations
    Posted in the Math Topics Forum
    Replies: 7
    Last Post: February 6th 2008, 11:04 AM

Search Tags


/mathhelpforum @mathhelpforum