I need to approximate, very simply and avoiding any mention of fluid dynamics because this is for schoolkids aged 14-16, the forces acting on a volume of air that is being pulled through a tube by a fan. My physics is failing me. Help! [more inside]
posted by dowcrag on Mar 9, 2012 - 6 answers

I have a 30' utility pole that I need to stand upright in a 6' deep hole. Complicating factor: the location is set back in the woods, so using heavy machinery or vehicles of any kind is not an option. [more inside]
posted by tr0ubley on Aug 13, 2010 - 26 answers

Help me understand electricity and physics and how they apply to motors. I have my head around electricity basics and electromagnetism, but I have a few unanswered questions about the more subtle aspects. [more inside]
posted by kaizen on Jun 22, 2008 - 11 answers

What, if any, is the relationship between bandwidth and power? [more inside]
posted by odinsdream on Nov 19, 2007 - 14 answers

Power generation: Let's say we have a hydroelectric dam. My understanding is that water turns a dynamo, which provides electricty. It seems like there would be a way to use the same water flow more than once. Could we make raceways of some indeterminate length to get the water back up to speed with sufficient force to turn a second dynamo? Could this be repeated so that a single water flow powers some n dynamos? What kind of constraints keep dams all over the world from doing this sort of thing?
posted by boo_radley on Aug 16, 2007 - 22 answers

Is it true that a horse is not capable of doing a horsepower worth of work? (And since horses are supposed to have such a high power to weight ratio are there any other animals that can do so?) [more inside]
posted by rongorongo on Oct 22, 2006 - 8 answers