8. Very small particles experience a drag force proportional to velocity: F=-bv. If the particle is...

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8. Very small particles experience a drag force proportional to velocity: F=-bv. If the particle is a sphere, radius r, then b = 6πηr, where n is the viscosity of the fluid through which the particle is moving. Grains of fine beach sand are roughly spherical and have a radius of about 50 micrometers. If a typical particle is born aloft by winds to a height of, say, 50 m, how long will it take to fall to the ground? Assume the falling grain reaches terminal speed almost immediately. Once aloft, the winds cease, and the particle is momentarily at rest. Most sand particles are composed largely of silicon dioxide, which has a density of 2600 kg/m³. The viscosity of air at 32°C is 1.9 × 10-5 N-s/m². 8. Very small particles experience a drag force proportional to velocity: F=-bv. If the particle is a sphere, radius r, then b = 6πηr, where n is the viscosity of the fluid through which the particle is moving. Grains of fine beach sand are roughly spherical and have a radius of about 50 micrometers. If a typical particle is born aloft by winds to a height of, say, 50 m, how long will it take to fall to the ground? Assume the falling grain reaches terminal speed almost immediately. Once aloft, the winds cease, and the particle is momentarily at rest. Most sand particles are composed largely of silicon dioxide, which has a density of 2600 kg/m³. The viscosity of air at 32°C is 1.9 × 10-5 N-s/m².

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Given Radius of the sand particle r 50 micrometers 50 106 m Density of silicon ... View the full answer