[填空题]
A 55-kg hiker starts ai 3z3o99g llyf:oed 0j+bu7k-g:ksmnt an elevation of 1600 m and climbs to the top of a 3300-m 0sj: g:k ko-e+udn7 bmpeak.
(a) What is the hiker’s change in potential energy? J
(b) What is the minimum work required of the hiker? J
(c) Can the actual work done be more than this? Explain why.