A wheel needs something else to make it useful. A simple wheel on an axle is useless unless it’s connected to something else and connecting a wheel is much more complicated than just making a wheel. There’s an article that mocks the fact that no one in Africa invented a wheel. Yeah, .. Well most people never did either. In addition a wheel can reduce the effort needed to move something 40 times.
From Wiki: The normal force between the 4 wheels and axles is the same (in total) 981 N. Assume, for wood, μ = 0.25, and say the wheel diameter is 1000 mm and axle diameter is 50 mm. So while the object still moves 10 m the sliding frictional surfaces only slide over each other a distance of 0.5 m. The work done is 981 × 0.25 × 0.5 = 123 joules; the work done has reduced to 1/40 of that of dragging.
Views: 5
