# impending motion

## Problem 542 | Friction on Wedges

**Problem 542**

What force P must be applied to the wedges shown in Fig. P-542 to start them under the block? The angle of friction for all contact surfaces is 10°.

## Problem 541 | Friction on Wedges

**Problem 541**

Determine the force P required to start the wedge shown in Fig. P-541. The angle of friction for all surfaces in contact is 15°.

## 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?

## 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?

## Problem 537 | Friction on Wedges

**Problem 537**

In Fig. P-537, determine the value of P just sufficient to start the 10° wedge under the 40-kN block. The angle of friction is 20° for all contact surfaces.

## 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.

## Problem 532 | Friction

**Problem 532**

In Fig. P-532, two blocks each weighing 1.5 kN are connected by a uniform horizontal bar which weighs 1.0 kN. If the angle of friction is 15° under each block, find P directed parallel to the 45° incline that will cause impending motion to the left.

## Problem 531 | Friction

**Problem 531**

A uniform plank of weight W and total length 2L is placed as shown in Fig. P-531 with its ends in contact with the inclined planes. The angle of friction is 15°. Determine the maximum value of the angle α at which slipping impends.

## Problem 530 | Friction

**Problem 530**

A plank 10 ft long is placed in a horizontal position with its ends resting on two inclined planes, as shown in Fig. P-530. The angle of friction is 20°. Determine how close the load P can be placed to each end before slipping impends.

## 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°.