What is the value of P in the system shown in Fig. 5.9(a) to cause the motion to impend?Assume the pulley is smooth and coefficient of friction between the other contact surfaces is 0.2.

The three flat blocks are positioned on the 30° incline as shown in Figure WDG – 3F, and a force P parallel to the incline is applied to the middle block. The upper block is pre vented from moving by a wire which attaches it to the fixed support. The coefficient of static friction for each of the three pairs of mating surfaces is shown. 1. Calculate the normal force (N) acting between 50-kg and 40-kg blocks (ANSWER: 680) and the maximum frictional resistance (N) on the surface between the 30-kg and 50-kg blocks (ANSWER: 76.5) 2. Calculate the maximum frictional resistance (N) on the surface between the 40-kg block and inclined surface (ANSWER: 459) and also determine the maximum value which P (in N) may have before any slipping takes place (ANSWER: 94).

PROBLEM 5: The upper block is attached to the ground as shown in the figure by a short rope. The coefficient of friction between the blocks is 0.25 while the angle of friction between the lower block and the horizontal ground is 30°. (a) Determine the tension in the rope, in N, when the lower block is about to move. (b) Determine friction force, in N, under the 900 N block when it is about to move. (c) Determine the horizontal force P, in N, required to initiate motion. 300 N P 900 N 30°

Blocks A and B have a masses of 150 kg and 280 kg, respectively. (Figure 2) The coefficient of static friction between A and B and between B and C is 0.290. The coefficient of static friction between the rope and peg E is 0.570. Pulley D rotates freely, and P = 27.0 N. If \theta = 60.0 degrees, what is the smallest magnitude, T, of tension, T, that causes block B to move? P A B E T