Independent measurements of two lengths are made. The results are x=95 +- 0.1 and y=2.30+-0.02 cm a) calculate the difference l=x-y and the corresponding uncertainty.
b) calculatr the relative uncertainty on the difference

The largest observatory complex in the world is on mauna kea, the tallest mountain on earth. what are some factors astronomers consider when selecting an observatory site? don’t forget practical ones. should astronomers, for example, consider building an observatory on denali (mount mckinley) or mount everest?