Please verify these are correct. No work needs to be shown unless I've made a mistake. Thank you.

Agas initially at p1 = 1 bar and occupying a volume of 0.5 liter is compressed within a piston–cylinder assembly to a final pressure p2 = 4 bar. (a) if the relationship between pressure and volume during the compression is pv = constant, determine the volume, in liters, at a pressure of 3 bar. (b) repeat for a linear pressure–volume relationship between the same end states. reference

If the ama of the inclined plane below is 2, calculate the ima and efficiency. ima = efficiency =

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?