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physics

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At a construction site a pipe wrench struck the ground with a speed of 45 m/s. (a) From what height was it inadvertently dropped? (b) How long was it falling?

  • physics -

    Kinematics Equations:

    Vx1 = Vx0 + axΔt
    (Vx1)^2 = (Vx0)^2 + 2axΔx
    Δx = Vx0Δt + ½ ax(Δt^2)


    Using the second kinematics equation, we can solve for Δx.

    (Vx1)^2 = (Vx0)^2 + 2axΔx


    Plug in what you know:

    (45 m/s)^2 = (0 m/s) + 2(9.8m/s^2)(? m)

    2025 m^2/s^2 = (19.6 m/s^2)(? m)

    (? m) = (2025 m^2/s^2)/(19.6 m/s^2)

    ? m = 103.3163265
    (sig figs) = 100 m

    Δx = 100m
    -----------------------------------

    Using the first kinematics equation, we can solve for Δt.

    Vx1 = Vx0 + axΔt


    Plug in what you know:

    Vx1 = Vx0 + axΔt
    45 m/s = 0 m/s + (9.8 m/s^2)(Δt)
    Δt = (45 m/s)/(9.8 m/s^2)
    Δt = 4.591836735
    (sig figs) =
    Δt = 4.6 s

    Let me know if that helped you!

  • physics -

    yes it did help and i get it now thank you

  • physics -

    shouldn't acceleration be -9.8 and not +9.8 since it freefalling in the negative direction?

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