You have a sample of crushed coal containing a range of particle sizes from 1 to 1000 m in diameter. You wish to separate the particles according to size by entrainment, by dropping them into a...

You have a sample of crushed coal containing a range of particle sizes from 1 to 1000 m in diameter. You wish to separate the particles according to size by entrainment, by dropping them into a vertical column of water that is flowing upward. If the water velocity in the column is 3 cm/s, which particles will be swept out of the top of the column, and which will settle to the bottom? (SG of the solid is 2.5.)