Alban Geissler, who developed the SKYRAY carbon fiber wing with Christoph Aarns, suggested after Baumgartner's jump that the wing he used was a copy of two prototype SKYRAY wings sold to Red Bull (Baumgartner's sponsor) two years earlier. - wiki
= (3,760 joule/sec) / (4,000 joule/sec)
= 3,760 / 4,000 = 0.94 = 94%
Answer:
the force of friction = fk = (uk)n = 402(uk)
the net force acting to accelerate bookcase = ma = (41)(0.12) = 4.9 N
the {assumed horizontal} push force = 65 N
so
65 - fk = 4.9
fk = 65 - 4.9 = 60 N
uk = 60/402 = 0.15 <= ANS
