2/58 A force F 60 N acts along the line AB. Determine the equivalent force–couple system at point C.
2/59 The top view of a revolving entrance door is shown. Two persons simultaneously approach the door and exert force of equal magnitudes as shown. If the resulting moment about the door pivot axis at O is 25N.m, determine the force magnitude F.
2/60 The indicated force–couple system is applied to a small shaft at the center of the plate. Replace this
system by a single force and specify the coordinate of the point on the x-axis through which the line of action of this resultant force passes.
2/61 The bracket is spot welded to the end of the shaft at point O. To show the effect of the 900-N force on the weld, replace the force by its equivalent of a force and couple M at O. Express M in vector notation.
2/62 As part of a test, the two aircraft engines are revved up and the propeller pitches are adjusted so as to result in the fore and aft thrusts shown. What force F must be exerted by the ground on each of the main braked wheels at A and B to counteract the turning effect of the two propeller thrusts? Neglect any effects of the nose wheel C, which is turned 90 and un-braked.
2/63 Replace the 10-kN force acting on the steel column by an equivalent force–couple system at point O. This replacement is frequently done in the design of structures.
2/64 Each propeller of the twin-screw ship develops a full-speed thrust of 300kN. In maneuvering the ship, one propeller is turning full speed ahead and the other full speed in reverse. What thrust P must each tug exert on the ship to counteract the effect of the ship’s propellers?
2/65 A lug wrench is used to tighten a square-head bolt. If 250-N forces are applied to the wrench as shown, determine the magnitude F of the equal forces exerted on the four contact points on the 25-mm bolt head so that their external effect on the bolt is equivalent to that of the two 250-N forces. Assume that the forces are perpendicular to the flats of the bolt head.
2/66 During a steady right turn, a person exerts the forces shown on the steering wheel. Note that each force consists of a tangential component and a radially-inward component. Determine the moment exerted about the steering column at O.
2/67 The 180-N force is applied to the end of body OAB. If θ = 50°, determine the equivalent force–couple system at the shaft axis O.
2/68 A force F of magnitude 50 N is exerted on the automobile parking-brake lever at the position x=250 mm. Replace the force by an equivalent force–couple system at the pivot point O.
2/69 The tie-rod AB exerts the 250-N force on the steering knuckle AO as shown. Replace this force by an equivalent force–couple system at O.
2/70 The combined drive wheels of a front-wheel-drive automobile are acted on by a 7000-N normal reaction force and a friction force F, both of which are exerted by the road surface. If it is known that the resultant of these two forces makes a 15 angle with the vertical, determine the equivalent force–couple system at the car mass center G. Treat this as a two-dimensional problem.
2/71 The system consisting of the bar OA, two identical pulleys, and a section of thin tape is subjected to the two 180-N tensile forces shown in the figure. Determine the equivalent force–couple system at point O.
2/72 Calculate the moment MB of the 900-N force about the bolt at B. Simplify your work by first replacing the force by its equivalent force–couple system at A.
2/73 The bracket is fastened to the girder by means of the two rivets A and B and supports the 2-kN force. Replace this force by a force acting along the centerline between the rivets and a couple. Then redistribute this force and couple by replacing it by two forces, one at A and the other at B, and ascertain the forces supported by the rivets.
2/74 The angle plate is subjected to the two 250-N forces shown. It is desired to replace these forces by an equivalent set consisting of the 200-N force applied at A and a second force applied at B. Determine the y-coordinate of B.
2/75 The weld at O can support a maximum of 2500 N of force along each of the n- and t-directions and a maximum of 1400 of moment. Determine the allowable range for the direction of the 2700-N force applied at A. The angle θ is restricted to 0 ≤ θ ≤ 90.
2/76 The device shown is a part of an automobile seatback-release mechanism. The part is subjected to the 4-N force exerted at A and a restoring moment exerted by a hidden torsional spring. Determine the y-intercept of the line of action of the single equivalent force.
0 Comments