Problem 540 | Friction on Wedges

Problem 540
As shown in Fig. P-540, two blocks each weighing 20 kN and resting on a horizontal surface, are to be pushed apart by a 30° wedge. The angle of friction is 15° for all contact surfaces. What value of P is required to start movement of the blocks? How would this answer be changed if the weight of one of the blocks were increased by 30 kN?
 

540-wedge-block-friction.gif

 

Problem 539 | Friction on Wedges

Problem 539
The block A in Fig. P-539 supports a load W = 100 kN and is to be raised by forcing the wedge B under it. The angle of friction for all surfaces in contact is f = 15°. If the wedge had a weight of 40 kN, what value of P would be required (a) to start the wedge under the block and (b) to pull the wedge out from under the block?
 

539-block-wedge.gif

 

Problem 533 | Friction

Problem 533
A uniform bar AB, weighing 424 N, is fastened by a frictionless pin to a block weighing 200 N as shown in Fig. P-533. At the vertical wall, μ = 0.268 while under the block, μ = 0.20. Determine the force P needed to start motion to the right.
 

Bar and block assembly

 

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