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Homework Help: Incline Forces Question

  1. Sep 24, 2010 #1
    1. The problem statement, all variables and given/known data

    A girl of mass mg=47 kg is pulling a sled up a slippery slope. The coefficient of friction between the girl's boots and the slope is µs=0.160; the friction between the sled and the slope is negligible. The girl can pull the sled up the slope with a ≤ amax=0.015 m/s2 before she begins to slip. Assume the rope connecting the girl to the sled is kept parallel to the slope at all times. The angle of the slope is θ = 6°.

    If the sled is being pulled up the slope with a=amax, what is the mass of the sled?

    mg = 47kg
    µs=0.160
    amax=0.015 m/s2
    θ = 6°

    2. Relevant equations

    fnet=ma
    Fs = Fnµs

    3. The attempt at a solution

    m(0.015m/s^2) = Fs - Mgsinθ
    m(0.015m/s^2) = 73.3N + m(9.81m/s^2)sin6
    m = 72.54kg

    72.54kg-45kg = 27.5kg


    i tried everything 27.5kg isn't the right answer what am i doing wrong someone please help i need to figure this out by tomorrow
     
  2. jcsd
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