Chapter 6, Problem 99P

Determine the contact force between the smooth 90-kg ball B and the horizontal bar, and the magnitude of the pin reaction at A. Neglect the weights of the bar and the pulley.

The four-bar linkage supports the homogeneous box of weight W. Neglecting the weight of the linkage, determine the horizontal pin reactions at A and B.

The uniform, 20-kg bar is placed between two vertical surfaces. Assuming sufficient friction at A to support the bar, find the magnitudes of the reactions at A and B.

The 180-kg uniform boom ABC, supported by a horizontal cable at B and a pin at A, carries a 320-kg load at C. Determine the force in the cable and the magnitude of the pin reaction.

The spring is connected to a rope that passes over the cylindrical surface and is attached to corner A of the rocker. The spring has a stiffness k and is undeformed when =0. When the weight W is suspended from A, the equilibrium position of the rocker is =30. Determine if this equilibrium position is stable. Neglect the weight of the rocker.

The 60-lb homogeneous door is supported by hinges at A and B, with only the hinge at B being capable of providing axial thrust. The cable CD prevents the door from fully opening when it is pulled by the 40-lb force acting perpendicular to the door. Draw the FBD for the door, and count the unknowns.

The center of gravity of the 3000-lb car is at G. The car is parked on an incline with the parking brake engaged, which locks the rear wheels. Find (a) the normal forces (perpendicular to the incline) acting under the front and rear pairs of wheels; and (b) the friction force (parallel to the incline) under the rear pair of wheels.

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 skid-steer loader has a mass of 1.18 Mg, and in the position shown. The center of mass is at G1. There is a 300-kg stone in the bucket, with center of mass at G2. There is a similar linkage on each side of the loader.   - Determine the magnitude of the reaction of the pair of wheels B on the ground. - Determine the magnitude of the reaction of the pair of wheels A on the ground. - Determine the magnitude of the force in the hydraulic cylinder CD. - Determine the magnitude of the force the force exerted on ED at the pin E.