Results 1 to 2 of 2

Math Help - show time travelled with uniform speed

  1. #1
    Newbie
    Joined
    Oct 2008
    Posts
    5

    show time travelled with uniform speed

    a lift starts from rest with constant acceleration 4m/s squared. it then travels with uniform speed and finally comes to rest with constant retardation 4m/s squared. the total distance travelled is D an the total time is t

    (i) show that the time for which it travelled with uniform speed is
    t squared-d
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by ronan116 View Post
    a lift starts from rest with constant acceleration 4m/s squared. it then travels with uniform speed and finally comes to rest with constant retardation 4m/s squared. the total distance travelled is D an the total time is t

    (i) show that the time for which it travelled with uniform speed is
    t squared-d
    here is a very brief outline of an approach:

    Motion 1:
    u = 0
    a = 4 m/s^2
    t = t_1
    v = v_1
    x = x_1

    Motion 2:
    x_2 = v_1 t_2

    Motion 3: By symmetry with motion 1
    u = v_1
    a = -4 m/s^2
    t = t_1
    v = 0
    x = x_1

    Given:

    t = 2 t_1 + t_2 .... (1)

    D = 2 x_1 + v_1 t_2 .... (2)

    Use the motion data to get x_1 and v_1 in terms of t_1 and substitute into equation (2).

    Then solve equations (1) and (2) simultaneously.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Speed-Time Graph 2
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: September 14th 2011, 02:55 PM
  2. Replies: 1
    Last Post: October 31st 2010, 08:09 PM
  3. The Speed of Time
    Posted in the Math Topics Forum
    Replies: 4
    Last Post: June 30th 2010, 04:19 PM
  4. Speed-time question..
    Posted in the Math Topics Forum
    Replies: 1
    Last Post: March 31st 2009, 01:47 AM
  5. Help with speed/distance/time and d/dx?
    Posted in the Calculus Forum
    Replies: 2
    Last Post: December 8th 2008, 02:55 AM

Search Tags


/mathhelpforum @mathhelpforum