Supposed an object is weighted with a spring balance, first in air then while totally immersed in water. The readings on the balance are 0.48N and 0.36N respectively. a) what is the upthrust on the object?
b) what is the mass of the fluid displaced?
c) what is the volume of the fluid displaced?
d) what is the density of the object?

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.