How much energy is stored in a spring that is compressed 0.650m if the spring constant is 725N/m?

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

Diamond will scratch quartz. true or false

What is the single most important equation in all of physics?