Friction between a surface and air or a liquid is call friction​

Africtionless piston-cylinder contains 50 l of saturated liquid r-134a. the piston has a mass and an area resulting in an applied pressure of 500 kpa on the refrigerant. the refrigerant is now heated until its temperature rises to 70∘c. calculate the work (in kj) done during this process.

Write a full page that sumerizes thermodynamics it’s from the website visionlearnig

Why does lightning travel from clouds to the ground?