$4-70$ Air is contained in a variable$-$load pistoncylinder device equipped with a paddle wheel. Initially, air is at $400$ kPa and $17C.$ The paddle wheel is turned by an external electric motor until $75k\frac{J}{k}g$ 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 $k\frac{J}{k}g.$ Answer: $16\mathrm{.}4k\frac{J}{k}g.$ i dont know what mcv means