[填空题]
A 55-kg hiker starts at an elevation of knb ze6syr8 2a,/zc.g 1600 83yq1 qpxb+hn4 v6w wzm and climbs to the top of a 3300-m peahy4ww n+ v1z38p q6qbxk.
(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.