To be rescued from the roof of a burning building, a \(70-\mathrm{kg}\) man must be able to jump straight up and catch hold of a rope ladder hanging from a helicopter. He has to raise his center of mass \(2.00 \mathrm{~m}\) above the roof to do so.

(a) If he crouches down such that his center of mass is \(0.50 \mathrm{~m}\) above the roof and his feet leave the roof when his center of mass is \(1.05 \mathrm{~m}\) above the roof, what minimum force must he exert on the roof to reach the ladder?

(b) A typical candy bar contains about \(850 \mathrm{~kJ}\) of food energy. How many candy bars does this jump require?