Name:Group members:

TAM 210/211 - Worksheet 8

1) A pumping unit is used to recover oil. When the walking beam ABC is horizontal, the forceacting in the wireline at the well head is 250 lb. The horse-head C weighs 60 lb and has a centerof gravity at Gc. The walking beam ABC has a weight of 130 lb and a center of gravity at GB,and the counterweight has a weight of 200 lb and a center of gravity at GW . The pitman, AD, ispin connected at its end and has negligible weight.

a) Draw a free-body diagram for the walking beam ABC

b) Use equilibrium equations to find the internal force in link AD.

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c) Draw a free-body diagram for the member ED

d) Use equilibrium equations to determine the torque M which must be exerted by the motor inorder to overcome the force at the well head.

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2) The double link grip is used to lift a beam that weighs 4kN. Hint: when modeling the interactionbetween the grip and the beam at points F and B, you should consider vertical and horizontal forces.

a) Draw the free-body diagram for link CD. Use the method of joint at D to determine the internalforce in link CD.

b) Draw the free-body diagram for the I-beam. Use the equilibrium equation (∑

M)F = 0 and∑Fy = 0 to determine the vertical reactions that the flange of the beam exerts on the jaw at F

and B.

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c) Draw the free-body diagram for member CAF .

c) Use equilibrium equations to determine the horizontal and vertical components of force actingon the pin A.

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3) A force F = 300 N is applied to the handle of the toggle clamp, as illustrated below.

a) Draw a free-body diagram for the handle.

b) Use equilibrium equations to determine the components of the force at pins B and C.

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c) Draw a free-body diagram for member GCD. Use this diagram to determine the resultingclamping force at A.

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