Astring under a tension of 56.9 n is used to whirl a rock in a horizontal circle of radius 2.55 m at a speed of 19.5 m/s. the string is pulled in and the speed of the rock increases. when the string is 1.18 m long and the speed of the rock is 52.5 m/s, the string breaks. what is the breaking strength (in newtons) of the string?

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.