A trough is filled with a liquid of density 865 kg/m3. The ends of the trough are equilateral triangles with sides 10 m long and vertex at the bottom. Find the hydrostatic force on one end of the trough. (Use 9.8 m/s2 for the acceleration due to gravity.)

Respuesta :

Answer:

[tex]F = 7.34 \times 10^6 N[/tex]

Explanation:

Since each side of the triangular end is of equilateral triangle with side length a = 10 m

so height of the triangle h = a sin60

h = 10sin60 = 8.66 m

now we will take a small strip of width L and thickness dy at a depth of y from top

so here width L is given as

[tex]L = 2ytan30 = 3.46 y[/tex]

now the force on this small strip is given as

[tex]dF = P . dA[/tex]

[tex]dF = (\rho g y). (3.46 y dy)[/tex]

now the total force on the triangular part

[tex]F = \int 3.46 \rho g y^2 dy[/tex]

[tex]F = (3.46 \rho g)(\frac{y^3}{3})[/tex]

now the limits of y is from y = 0 to y = 8.66 m

so we have

[tex]F = 3.46(1000)(9.8)(\frac{8.66^3}{3})[/tex]

[tex]F = 7.34 \times 10^6 N[/tex]