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Physics

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The coefficient of kinetic friction for a 22 kg bobsled on a track is 0.15. What force is required to push it down a 6.0° incline and achieve a speed of 64 km/h at the end of 75 m?

  • Physics -

    First calculate the required acceleration, a, with suitable units of m/s^2.

    Vfinal = 64 km/h = 17.78 m/s
    Vfinal = sqrt(2 a X)
    a = (Vfinal)^2/(2X) = 2.11 m/s^2

    Then use Newton's second law, along the direction of motion. If the pushing force is F, the net force in the direction of motion is
    Fnet = F + M*g sin6 -M*g*cos6*0.15
    = M a
    Use that equation to solve for F.

    You could also use a conservation of energy method. (Work applied) = F*X
    = PE loss + KE gain + (work against friction)

  • Physics -

    45.326

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