¡Descarga Cálculo de peso y densidad de etanol y velocidad terminal de un bloque en aceite y más Ejercicios en PDF de Mecánica de Fluidos solo en Docsity!
1.- The specific gravity of ethyl alcohol is 0,79. Calculate its specific weight (in
both pounds per cubic foot and kilonewtons per cubic meter) and mass density
(in both slugs per cubic foot and kilograms per cubic meter).
Development: y=( 0,19) (62,4 lb/ft 3 ) y=49,3 lb/ft 3 y=(0,79)(9,8 kN ) y=7,74 kN /m 3 p=(0,79)( 1 000 kg/m 3 ) p= 790 kg/m 3 p=(^ 0,79)^ (1,94 lbf /ft 3 ) p=1,53 lbf /ft 3 Formula: γ=s. g. s. g .water p=s. g. pwater Data: s. g .=0, s. g .water= 9800 s. g .water=62,4 lb/ ft 3 pwater = 1 000 kg/m 3 pwater =1,94 lbf /ft 3
2.- A square block weighing 1,1 kN and 250 mm on an edge slides down an
incline on a film of oil 6,0 m thick. Assuming a linear velocity profile in the oil,
what is the terminal speed of the block? The viscosity of the oil is 7 mPa s.
Development: t=0,007 N s /m 2 ( du 6 × 10 − 6 m
F= 1 166,66(0,250 m) 2 =72,91 u 1 100 N sin( 20 )=72,91u=5,16 m/s Data: W =1,1 kN L= 250 mm dy =0,0060 mm μ= 7 mPa s=0.007 N s/m 2 Formula: t=( du dy
)( L
2 ) t=W sin 20
4.- Calculate the capillary effect in millimeters in a glass tube of 4 mm diameter,
when immersed in (i) water, and (ii) mercury. The temperature of the liquid is 20
°C and the values of the surface tension of water and mercury at 20 °C in
contact with air are 0,073575 N/m and 0,51 N7m respectively. The angle of
contact for water is zero that for mercury 130°. Take density of water at 20 °C as
equal to 998 kg/m^3.
Data: D= 4 mm T (^) water = 20 ° C T (^) mercury= 20 ° C twater =0,073575 N /m tmercury=0,51 N /m p= 998 kg/m^3 g=9,81 m/ s 2 Development: Water h=( 4 )(0,073575 N /m)(cos θ)/( 998 kg /m 3 )(9,81m/s 2 )( 4 × 10 − 3 ) h=0,073575 m=7,51 mm Mercury P=13,600 kg /m 3 h=( 4 )(0,51 N /m)cos 130 °θ / 13600 (9,81)( 4 × 10 − 3 )=−2,46 × 10 − 3 m=−2,46 mm Formula: h= 4 σ cos Θ ρ g d
5.- A piece of wood of SG = 0,651 is 3 in square and 5 ft long. How many
pounds of lead weighing 700 lbf/ft^3 must fastened at one end of the stick so that
it will float upright with 1 ft of water?
Data: Formula: Development:
