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Homework Help: Biomechanics statics problem

  1. Feb 15, 2017 #1
    1. The problem statement, all variables and given/known data
    A man deals his bicycle up a 5 percent road at constant speed. Man+bicycle mass=90 kg with mass centre G. 1)Access direction of frictional forces 2) explain why frinctional force in front wheel can be neglected having a const. speed taking front wheel as FBD 3) Find normal forces

    2. Relevant equations
    Fy=0 Nf +Nr =G

    3. The attempt at a solution
    Direction is upward
    Fy=0 Nf +Nr =G
    M= 0. 0.46G= 1.08Nf.
    Nf= 375.67N

    Now I don't know how to show that friction in front wheel can be neglected

    Attached Files:

    Last edited by a moderator: Feb 15, 2017
  2. jcsd
  3. Feb 15, 2017 #2
    I'm not 100% sure, maybe someone else can pitch in, but:

    The normal forces in the front wheel can be neglected because F = ma and since the front wheel is at a const. speed, a = 0 which implies summation of Fx = 0. Therefore friction force must be zero.

    This should also apply to the back wheel, ( but I'm not entirely sure if it will have a=0 since it is connected to a gear...)

    Also, your calculations are unclear to me in (3), so I can't provide feedback there.
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