When a 40-n force, parallel to the incline and directed up the incline, is applied to a crate on a frictionless incline that is 30 above the horizontal, the acceleration of the crate is 2.0 m/s2 , up the incline. the mass of the crate is: ?

Can you use radiation to generate electricity

It is really hard for me right know

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.