Problem 507 | Friction

Problem 507
The 2225-N block shown in Fig. P-507 is in contact with 45° incline. The coefficient of static friction is 0.25. Compute the value of the horizontal force P necessary to (a) just start the block up the incline or (b) just prevent motion down the incline. (c) If P = 1780 N, what is the amount and direction of the friction force?

Block on an incline pushed by horizontal force


Problem 506 | Friction

Problem 506
A 400 lb block is resting on a rough horizontal surface for which the coefficient of friction is 0.40. Determine the force P required to cause motion to impend if applied to the block (a) horizontally or (b) downward at 30° with the horizontal. (c) What minimum force is required to start motion?


Friction is the contact resistance exerted by one body when the second body moves or tends to move past the first body. Friction is a retarding force that always acts opposite to the motion or to the tendency to move.

Problem 002-mm | Method of Members

Problem 002-mm
Members AB and BC shown in Fig. F-002(MM) are pinned together at point B, and are pinned to the floor at points A and C. The structure supports a pulley at point B with which, a person is hoisting a 2.0 kN load. Member BC has a weight of 1.6 kN, which may be considered to act at its center, while AB is made of strong-light material and has negligible weight. Determine the value of the external support reactions at A and C.