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It is desired to design a system for controlling the rate of extension of the fire-truck ladder during elevation of the ladder so that the bucket B will have vertical motion only. Determine if the elongation rate of the hydraulic cylinder is 0.7 ft/sec and θ = 21°, L = 13 ft, h = 3.2 ft, b = 9 ft, and x = 5 ft.

Respuesta :

Answer:

The elongation rate is 1.17 ft/s

Explanation:

The expression is:

-(L - x)θsinθ + x*cosθ = 0

x = (L+x)θ * tanθ

CD² = 2b²(1 - cos(θ + δ))

2CC = 2b²θsin(θ + δ)

[tex]O=\frac{CC*C\sqrt{2^{2}(1-cos(O+Y) } }{b^{2}sin(O+Y) }[/tex]

Where O = θ and Y = δ

[tex]O=\frac{\sqrt{2} }{b} (\frac{\sqrt{1-cos(O+Y)} }{\sqrt{1-cos^{2}(O+Y) } } )C[/tex]

[tex]x=(L+x)tanO\frac{\sqrt{2} C}{b\sqrt{1+cos(O+Y)} }[/tex]

Where

C = 1 ft/s

θ = 28°

L = 13 ft

h = 3.2 ft

b = 9 ft

x = 5 ft

δ = sin⁻¹(h/b) = sin⁻¹(3.2/9) = 20.83°

Replacing:

[tex]x=\frac{(13+5)*tan(28)*\sqrt{2}*1 }{9*\sqrt{1+cos(28+20.83)} } =1.17ft/s[/tex]