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Anonymous
Anonymous asked in Science & MathematicsPhysics · 2 months ago

Physics help?

A pole vaulter leaves the ground to travel 4.0 m up and over the bar, and then another 4.0 m back to the ground. It takes 1.81 s for the whole trip. Calculate the velocity with which she left the ground?

1 Answer

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  • 2 months ago

    so it takes 0.905 s up and the same down.

    v = gt = 9.8 x 0.905 = 8.87 m/s

    check

    h = ½gt² = ½9.8•0.905² = 3.77 m

    which is NOT 4 m, so something is off....

    if we use the 4 m number

    v = √(2gh) = √(2•9.8•4) = 8.85 m/s

    take you pick.

    falling object starting from rest

    h is height in meters, t is time falling in seconds,

    g is acceleration of gravity, usually 9.8 m/s²

    v is velocity in m/s

    h = ½gt²

    t = √(2h/g)

    v = √(2gh)

    h = v²/2g

    v = gt

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