Mecánica - Trabajo Colaborativo

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- A crate is supported by three cables as shown. Determine the weight of the crate knowing that the tension in cable AD is 616 lb.

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Análisis del DCL

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(Equilibrio de traslación) [pic 122]

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- A container of weight W is suspended from ring A. Cable BAC passes through the ring and is attached to fixed supports at B and C. Two forces P = Pi, and Q =Qk, are applied to the ring to maintain the container in the position shown. Knowing that W = 376 N, determine P and Q. (Hint: The tension is the same in both portions of cable BAC).

Realizando el DCL[pic 123][pic 124]

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- The flat plate shown in Fig (a) is acted on by the three couples. Replace the three couples with (1) a couple – vector: (2) two forces, one acting along the line OP.

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- Replace two couples shown by a single equivalent couple.

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- Determine the magnitude of the moment of the 150 N force about point O and find the direction cosines of the moment vector.

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- The forces P and Q act on the handles of the wrench. If P – 32lb and Q – 36 lb., determine the combined moment of the two forces about the z axis.

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- A section of a piping system is acted on by the three couples shown in fig A. Determine the magnitude of the resultant couple vector Cr – and its direction cosines, given that the magnitudes of the applied couples are C1 – 50 N.m C2 – 90 N.m C3- 140 N.m

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- Determine the magnitude of the single couple that its equivalent to the two couples shown.

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- The steering column of the rack – and – pinion steering mechanism lies in the XZ plane. The tube AB of the steering gear is attached to the automobile chassis at A and B. When the steering wheel is turned, the assembly is subjected to the four couples shown: the 3 N.m couple applied by the driver to the steering wheel, two 1.8 N.m couple (one at each wheel), and the couple formed by the two forces of magnitude F acting at A and B. If the resultant couple acting on the steering mechanism is zero, determine F and the angle o( the magnitude and direction of the bearing reactions).

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Calculamos el torque en el volante:

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Hallamos el par originado por la fuerza F:

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Por condición del problema: [pic 156]

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Resolviendo:

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- To open the high pressure water cock, a 12 lb. horizontal force must be applied to the handle at A. Draw the FBD of the handle, neglecting its weight. Count the unknowns.

DIAGRAMA DECUERPO LIBRE

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- Draw the FBD of the entire frame, assuming that friction and the weights of the member are negligible. How many unknowns appear on this FBD. Draw an FBD of member CE of the frame described in the previous problem. How many unknowns appear on this FBD.

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