Problem 527 and Problem 528 | Friction

Problem 527
A homogeneous cylinder 3 m in diameter and weighing 30 kN is resting on two inclined planes as shown in Fig. P-527. If the angle of friction is 15° for all contact surfaces, compute the magnitude of the couple required to start the cylinder rotating counterclockwise.
 

Cylinder resting on the corner of two inclined planes

 

Problem 528
Instead of a couple, determine the minimum horizontal force P applied tangentially to the left at the top of the cylinder described in Prob. 527 to start the cylinder rotating counterclockwise.
 

Problem 526 | Friction

Problem 526
A ladder 6 m long has a mass of 18 kg and its center of gravity is 2.4 m from the bottom. The ladder is placed against a vertical wall so that it makes an angle of 60° with the ground. How far up the ladder can a 72-kg man climb before the ladder is on the verge of slipping? The angle of friction at all contact surfaces is 15°.
 

Problem 525 | Friction

Problem 525
A uniform ladder 4.8 m ft long and weighing W lb is placed with one end on the ground and the other against a vertical wall. The angle of friction at all contact surfaces is 20°. Find the minimum value of the angle θ at which the ladder can be inclined with the horizontal before slipping occurs.
 

Problem 524 | Friction

Problem 524
A horizontal arm having a bushing of 20 mm long is slipped over a 20-mm diameter vertical rod, as shown in Fig. P-524. The coefficient of friction between the bushing and the rod is 0.20. Compute the minimum length L at which a weight W can be placed to prevent the arm from slipping down the rod. Neglect the weight of the arm.
 

Bushing and rod system

 

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