On what factors does coefficient friction force and static friction force depend?

Ais useful when you need a simple machine to you separate two things. a. lever b. screw c. pulley d. wedge

Which is not true about oxygen-17 and oxygen-18?

Air initially at 0.75 bar, 1000 k, and occupying a volume of 0.12 m^3 undergoes two processes. process 1-2: the air is compressed isothermally until the volume is halved. process 2-3: the air undergoes a constant pressure process until the volume is halved again. assume ideal gas behavior. a) determine the mass of the air, in kg. b) the work and the heat transfer for each of the two processes, in kj. (100 kj = 1 bar . m^3)