This stone on Dent is obviously a glacial erratic and lots like the Ennerdale Granophyre. You can see the origin in the distance up to 10km away. My poles are 1.4m long so the stone is approximately 1m x 1m x 0.5m = 0.5 cubic metres. The rock gas a density of say 3000 kg/m^3 to 1sf. Mass of rock = 1500kg. Weight of rock = approx 15000N. Now if I wanted to calculate the work done by the glacier moving the stone 10km, which force would I use? Could I say that the work has been done against gravity holding the stone up? Or is it work done against friction? And if so, is that friction under the stone, which might be held fast anyway, or friction under the glacier? Can't resolve this at the moment.
