In the sport of skeleton a participant jumps onto a sled (known as a skeleton) and proceeds to slide down an icy track, belly down and head first. in the 2010 winter olympics, the track had sixteen turns and dropped 126 m in elevation from top to bottom. (a) in the absence of nonconservative forces, such as friction and air resistance, what would be the speed of a rider at the bottom of the track? assume that the speed at the beginning of the run is relatively small and can be ignored. /s (b) in reality, the gold-medal winner (canadian jon montgomery) reached the bottom in one heat with a speed of 40.5 m/s (about 91 mi/h). how much work was done on him and his sled (assuming a total mass of 118 kg) by nonconservative forces during this heat?

bacteria that live on the ocean floor are sustained by phytoplankton. phytoplankton, microscopic marine photosynthetic organisms, have a vastly significant role to play not only in the marine food web of which they’re part of, but also on a more global scale. despite their infinitely small size in comparison to other marine organisms, these tiny creatures occupy an immensely important ecological niche: they are the foundation of the marine food web, and as primary producers, play key roles in supporting all other organisms in the marine environment, as well as in the regulation of the earth’s climate through the sequestration of carbon, oxygen production, and other related processes. phytoplankton account for roughly half of all global primary productivity; therefore, their significance extends far beyond the marine environment alone. there is an intriguing sense of irony in the realization that these tiny living beings that often live out their existence unnoticed and undetected by the rest of the world, have such a far-reaching impact on the lives of virtually all other living organisms on the planet, particularly on those in the marine environment. the world that we have become accustomed to has been and is continuously shaped by the workings of these miniscule yet vital “plants of the sea”.

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