A 0.5 kg ball is about to roll off the edge of a 1.5 m tall table. What is its current potential energy? (g = 9.8 ms²) ?

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  • NCS
    Lv 7
    2 months ago

    Depends on your frame of reference. If you consider the ground to be the point of 0 gravitational potential energy, then at the tabletop

    GPE = 0.5kg * 9.8m/s² * 1.5m = 7.4 J

    But if the tabletop is your 0 GPE height, then at the tabletop

    GPE = 0 J

    And if the ceiling 2 m above the table is your 0 GPE reference, then at the tabletop

    GPE = 0.5kg * 9.8m/s² * -2m = -9.8 J

    The 0 GPE height can be set anywhere; it's the CHANGES in height that matter.

    Hope this helps!

  • 2 months ago

    PE = mgh

    so, 0.5 x 9.8 x 1.5 => 7.35 Joules

    :)>

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