If the wind applies a force of 13.2 lb to the sign at the geometric center of the sign surface, will the sign tip over? if so, how much evenly distributed weight (sand bags) should be added to the base of the sign to keep it from tipping when the wind blows?

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.