Aboat has a velocity of 5m/s north with respect to a river. it aims to reach point a, directly north across the river, which is 40 m wide. however, because of the river speed it reaches another point
b. if the speed of the current is 2m/s to the east, calculate the time of the trip and the distance between points a and
b.

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.