The winning time for the 2005 annual race up 86 floors of the empire state building was 10 min and 49 s . the winner's mass was 60 kg . if each floor was 3.7 m high, what was the winner's change in gravitational potential energy? if the efficiency in climbing stairs is 25 %, what total energy did the winner expend during the race? how many food calories did the winner "burn" during the race? what was the winner's metabolic power in watts during the race up the stairs? express your answer using two significant figures.

Ametal ring 4.20 cm in diameter is placed between the north and south poles of large magnets with the plane of its area perpendicular to the magnetic field. these magnets produce an initial uniform field of 1.12 t between them but are gradually pulled apart, causing this field to remain uniform but decrease steadily at 0.240 t/s . (a) what is the magnitude of the electric field induced in the ring? (b) in which direction (clockwise or counterclockwise) does the current flow as viewed by someone on the south pole of the magnet?