Untitled docume8nt

6

X Incorrect The machine shown is used for moving heavy items such as pallets of bricks around construction sites. For the horizontal boom position shown, determine the force in each of the two hydraulic cylinders AB (positive if in tension, negative if in compression). The mass of the boom is 1660 kg with mass center at G1, and the mass of the cube of bricks is 2100 kg with mass center at G2. Assume a = 965 mm, b = 120 mm, c = 610 mm, d = 755 mm, e = 1845 mm, and f = 2965 mm. d f e В a G1 Answer: AB = i 180.794 kN

mass The power unit A of the tractor-scraper has a mass of 5.9 Mg with mass center at G₁. The fully loaded trailer-scraper unit B has a of 22.7 Mg with mass center at G₂. Positioning of the scraper is controlled by two hydraulic cylinders EF, one on each side of the machine. Calculate the compression F in each of the cylinders and the magnitude of the force supported by each of the pins at H, one on each side. Assume that the wheels are free to turn so that there are no horizontal components of force under the wheels. Answers: F= i H= i 870 1480 1480 11701480540 Dimensions in millimeters 1 KN KN

6.1

The system below is composed of a uniform, slender rod. The mass of each section can be described using its density, p =2.2 kg/m. The distances on the diagram below are: a = 190 mm, b= 310 mm, and c= 430 mm. Determine the magnitudes of the force and moment reactions at the built-in support O. (Hint: Recall the support reactions required for a built-in support. The mass of each section varies according to its length.) b 3 26 3 3a

Crane boom of mass 450 kg with its center of mass at C isstabilized by two cables AQ and BQ. The crane boom lies in the y–zplane. Find the forces in each cable (P=20 kN)

The square steel plate has a mass of 1740 kg with mass center at its center G. Calculate the tension in each of the three cables with which the plate is lifted while remaining horizontal.

A fixed crane has a mass of 1000 kg and is used to lift a 2400 kg crate. It is held in place by a pin at A and a rocker at B. The center of gravity of the crane is located at G. The reaction force on the roeker B is.

The force P on the handle of the positioning lever produces a vertical compression of 56 lb in the coiled spring in the position shown. Determine the magnitude of the corresponding force exerted by the pin at O on the lever. Assume a = 3.4 in. b = 8.6 in. P b. Answer

One of the smooth vertical walls supporting end B of the 100-kg uniform shaft is turned through a 40° angle as shown here. End A is supported by the ball-and-socket connection in the horizontal x-y plane. Calculate the magnitudes of the forces P and R exerted on the ball end B of the shaft by the vertical walls C and D, respectively. Assume a = 5.6 m, b = 1.8 m, L = 6.9 m, and 0 = 40°. A Answers:

4. Not a graded question.

The machine shown is used for moving heavy items such as pallets of bricks around construction sites. Determine the force in the single hydraulic cylinder CD (positive if in tension, negative if in compresssion). The mass of the cube of bricks is 1980 kg with mass center at G2. You may neglect the effects of the mass of the forklift components. Assume a = 770 mm, b = 185 mm, c = 500 mm, d = 45 mm, e = 810 mm. a E- D e d Answer: CD = i ! kN

The jaws and bolts of the wood clamp in Fig- are parallel. The bolts pass through swivel mounts so that no moments act on them. The clamp exerts forces of 300 N on each side of the board. Treat the forces on the boards as uniformly distributed over the contact areas and determine the forces in each of the bolts. Show on a sketch all forces acting on the upper jaw of the clamp. D 100 mm 150 mm B H00 mm75 mm-100 mm-

2.0 m 100 kg 2.0 m 0.5 m 1.5 m 1.5 m The pulley at E is frictionless. Point B is a pinned connection; support A is a fixed support. The pin at C is in a smooth slot. Determine the magnitude of normal force the pin C exerts on the smooth slot, - N. Determine the magnitude of of the y-component of the reaction force at B, By. N. Determine the magnitude of of the x-component of the reaction force at B, Bx- N.