A helicopter lifts a 86 kg astronaut 20 m vertically from the ocean by means of a cable. The acceleration of the astronaut is g/11. How much work is done on the astronaut by

(a) the force from the helicopter and
(b) the gravitational force on her? Just before she reaches the helicopter, what are her
(c) kinetic energy and
(d) speed?

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.