A cave rescue team lifts an injured spelunker directly upward and out of a sinkh
ID: 1975409 • Letter: A
Question
A cave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. The lift is performed in three stages, each requiring a vertical distance of 10.0 m: (1) the initially stationary spelunker is accelerated to a speed of 4.80 m/s; (2) he is then lifted at the constant speed of 4.80 m/s; (3) finally he is decelerated to zero speed. How much work is done on the 89.0 kg rescuee by the force lifting him during each stage?Work done on rescuee during stage (1)
__________kJ
Work done on rescuee during stage (2)
_________kJ
Work done on rescuee during stage (3)
__________ kJ
Explanation / Answer
a) In stage 1 a=0.288 so work done is m*a*x=256.32J b) In stage 2 a=0 so work done is 0 c) In stage 3 a=-0.288 so work done is -256.32 J