IIT JEE , AIEEE Forum - Physics , Mechanics

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at the top , P/

= gh = 9.8 (4m) = 39.2
                  Av = .51 m^3/s
                  0.196 m^2 v = .51
                  v = 2.602m/s
total energy per unit mass at top = P/

+ 1/2 v² + gh
= 39.2 + 1/2 (2.602)² + 9.8(3.6)
= 77.865 J ........................(1)
at the bottom, P/

= gh = 9.8 (5m) = 49
                      Av = .51m^3/s
                      0.126 m^2v = .51m^3/s
                      v = 4.048 m/s
total energy per unit mass at bottom = P/

+ 1/2 v² + gh
= 49 + 1/2(4.048)² + 0
= 57.193J ..................(2)
from (1) and (2) loss in energy per unit mass,
= 77.865 - 57.193
= 20.672 J/kg

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