Answer:
a) 1500 j
b) 3000 j
c) 34.64 m/s
Explanation:
at halfway point 1/2 of the potential energy has been converted to kinetic energy
so 1 /2 P E = Â 1500 j
  it will still have the OTHER half of its PE   1500 j
c) PE will be entirely converted to KE when it is at the bottom
    KE = 1/2 m v^2
    3000 = 1/2 (5)(v^2)   show  v = 34.64 m/s