How Is the Force on the Boom Hinge Calculated in a Wrecking Ball Setup?

AI Thread Summary
In a wrecking ball setup, the force on the boom hinge can be calculated using static equilibrium equations, specifically the sum of forces in both horizontal and vertical directions. The total torque on the system is initially calculated as 16,000 N, but this value is incorrect as pointed out in the discussion. To accurately determine the forces, three equations are needed: two for the forces and one for the moments, taking into account the angles of the boom and support cable. The angles used in calculations should be verified to ensure they correspond correctly to the geometry of the setup. A systematic approach involving simultaneous equations will lead to the correct values for the forces acting on the hinge.
anelmarx
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Homework Statement


A wrecking ball weighing 4800N is supported by a uniform boom of wieght 3600N. A support cable runs from the top of the boom to the tractor. the angle between the support cable and the horizontal is 32degrees and the angle between the boom and the horizon is 48degrees.
Find the magnitude of the force exerted on the lower end of the boom by the hinge.


Homework Equations


Sum of Fx=0
Sum of Fy=0


The Attempt at a Solution


I have already established that the total torque on the rope is = 16 000N
So then I am thinking that this might be right:

Sum of Fx=0=H-Tsin58degrees
H=16000*sin58degrees
H=13600N

Sum of Fy=0=V-4800-3600-Tcos58degrees
V=4800+3600+16000*cos58degrees
V=16900N

I just cannot wrap my head around the angles vs the magnitude. eg. vertical force of weight of boom is 3600N but should I not include the angle somehow?
And then the 58degrees is taken from 16+42 at the top of the boom - it that correct? Or should it be 32degrees? Really confused by all these angles.
 
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anelmarx: You have three unknowns in your above post, but you posted only two equations (which are correct). You need one more equation, summation of moment. Assume the boom length is L. The weight of the boom acts downward at the boom midspan. Section-cut the slanted cable at the top of the boom, if you wish, and place the slanted cable tensile force T at this section cut. Now sum moments of the entire system. Solve simultaneously for the three unknowns. Your angles are OK. T is not 16 000 N. Try it again. You are almost there.
 
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