Respuesta :

Answer:

Second choice

Explanation:

I suppose ME is the same as POTENTIAL energy

ME = mgh =  70 * 10 * 12 = 8400j

  Half way down,   4200 j is converted to Kinetic Energy

       1/2 m v^2 = 4200

       1/2 (70)  v^2 = 4200       v = 10.95 m/s

  Just before impact ALL of the 8400 j is now KE
      1/2 (70)v^2 = 8400          v = 15.49 m/s

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