Question #6624a

1 Answer
A08
Jan 28, 2018
  1. Total energy at the top of cliff

    #mgh=20000J#
    Inserting various values and taking #g=10ms^-2#
    #50xx10xxh=20000#
    #=>h=20000/(500)=40m#
    (matches with the given number in the text.

  2. Half way down #1/2# of her energy has been converted in to her kinetic energy. If #v# is her velocity half way down we get
    #1/2mv^2=10000#
    #=>v^2=10000xx2/50=400#
    #=>v=sqrt400=20" ms"^-1#
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