How long have simple machines been around?

Group of answer choices

850 years

millions of years

thousands of years

hundreds of years

Apure substance is a)-mixture of various chemical elements or compounds b)-substance that has a fixed chemical composition throughout c)-mixture that is homogeneous (such as air) d)-all the answers

Explain in your own word the concept of a solid solution, in alloys, and how it can be created.

Steam at a pressure of 100 kpa and a quality of 50% initially fills a rigid vessel having a volume of 0.5 m^3. the steam is then heated, causing the pressure in the vessel to rise to 150 kpa. determine: i. the mass of the steam in the vessel. ii. the temperature and quality of the steam after the heating process. ii the mass of the vapour, mg and liquid, m in the vessel after the heating process. if the steam in the vessel is now further heated, what would the pressure and temperature in the vessel be when all steam has turned into saturated vapour? b. sketch the processes in part (a) and part (b) on p-v and t-v diagrams, indicating clearly the temperatures, pressures and the paths. c. (0.59kg, 111.4°c, 73%, 0.4307kg, 0.1 593kg, 2.11 bar, 121.84°c)