Suppose s(t) is the position of an object moving along a line at time t is greater than or equal to 0. what is the average velocity between the times t=a and t=b? what is the instantaneous velocity at t=a?

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.