Newton wheel

A 1,000 kg (metric ton) car accelerating from 0—30 m/s (68 mph) in 6 seconds, thus requires an average force of 5,000 neivtoiis. This is a force approximatel y half the tveight of the car. It is likel y that the car would burn rubber as the drive wheels spun on the road during this acceleration. To accelerate to the same speed in 12 seconds would require a force of onl y 2,500 newtons. 

Much of Newton s work involved rotational motion, particularly circular motion. The velocity s direction constantly changes, requiring a centripetal acceleration. This centripetal acceleration requires a net force, the centripetal force, acting toward the center of motion. Centripetal acceleration is given by a(central)=v /R where v is the velocity s magnitude and R is the radius of the motion. Hence, the centripetal force F(central) = mv /R, where m is the mass. These relationships hold for any case of circular motion and furnish the basis for thrills experienced on many amusement park rides such as ferris wheels, loop-the-loops, merry-go-rounds, and any other means for changing your direction rather suddenly. Some particular examples follow. 

The rotation of the wheel is governed by Newton s law F = ma, expressed as a balance between the applied torques and the rate of change of angular momentum. Let / denote the moment of inertia of the wheel. Note that in general / depends on... 

It was widely appreciated by Newton and his contemporaries that the compressive effect of the Cartesian aether was equivalent to some hypothetical force, often likened to gravity, that puUs a planet towards the central star and bends its rectilinear motion around into a closed curve. The magnitude of such a force had to be sufficient to balance the centrifugal, potter s wheel, effect and so prevent the rotating planet firom escaping. It became vitally important to calculate the centripetal acceleration that was needed to stabilize such a closed orbit. 

Melt strength was measured at 190 °C on a Gottfert Rheotens . The barrel length of the rheometer was 285 mm and width ca. 12 mm. A 30/2 die for the extrusion of the blend was utilized. The sample was allowed to melt in the barrel for ten minutes, followed by extrusion through the die at a rate of 0.27 mm/s (shear rate of ca. 38 s" ). As the sample extruded out of the die, it passed through the wheels of the Rheotens , which pulled the molten polymer strand in a downward motion. As the wheel velocity increased, the force required to pull the molten extrudate was measured in centi-Newtons or cN. 

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