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Unformatted text preview: 57:020 Mechanics of Fluids and Transport Fall 2010 EXAM2 Solutions Problem 1: Momentum equation (Chapter 5) Information and assumptions 1 = 760 kPa; 2 = = 101 kPa 1 = 5 cm; 2 = 2 cm = 788.42 kg/m 3 for alcohol No losses in the nozzle flow Find Alcohol jet velocity V 2 and the force F required to hold the plate stationary Solution (a) As no losses in the nozzle flow, one can apply the Bernoulli equation between the sections 1 and 2 to find 2 . By knowing that 1 = ( 2 1 ) 2 = ( 2 1 ) 2 2 from the continuity equation and that 1 = 2 , the Bernoulli equation can be written as 1 + 1 2 2 1 2 2 2 = 2 + 1 2 2 2 (+3 points) or 2 = 2( 1 2 ) [1 ( 2 1 ) 4 ] Thus, 2 = 2(760,000 Pa 101,000 Pa) 788.42 kg m 3 [1 (0.02 m 0.05 m ) 4 ] = 41.42 m s (+2 point) (b) For a control volume that encompasses the jet from section 2 and the plate, a momentum analysis gives = ( 2 ) + 0 = 2 2 2 (+4 points) Thus, =...
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This note was uploaded on 12/08/2011 for the course MECHANICS 57:020 taught by Professor Fredrickstern during the Fall '10 term at University of Iowa.
 Fall '10
 FredrickStern
 Momentum

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