2. The force P is applied to the block m kg, which is stationary before the force is applied. Determine the magnitude and direction of the friction force f exerted by the horizontal surface on the block.

Block A has a mass of 26 kg and block B has a mass of 43 kg. The two blocks are stacked on the ramp with an incline of 0 = 33°. Determine the largest horizontal force F that can be applied to block B without either block moving for each of the following two cases: a.) The friction coefficient for the contact between blocks A and B is Ha1 = 0.62 and the friction coefficient for the contact between block A and the ramp is H2 = 0.26. b.) The friction coefficient for the contact between blocks A and B is Ha1 = 0.62 and the friction coefficient for the contact between block A and the ramp is H2 = 0.65. F В A Part a) The limiting slip condition occurs at the contact betveen A and the ramp ♥ N The maximum force before either block A or B slips is Part b) The limiting slip condition occurs at the contact between A and B N. The maximum force before either block A or B slips is

The force Pis applied to the 52-kg block when it is at rest. Determine the magnitude and direction of the friction force exerted by the surface on the block if (a) P = 0, (b) P = 184 N, and (c) P = 245 N. (d) What value of P is required to initiate motion up the incline? The static and kinetic coefficients of friction between the block and the incline are ug = 0.20 and µ = 0.16, respectively. The friction force is positive if up the incline, negative if down the incline. 52 kg 21° H, = 0.20 H = 0.16 13 Answers: (a) F= i N (b) F = i N (c) F= i N (d) P= i N

A B 2 ft For the frame shown, determine all support and connection forces on each member. The 400-lb-ft couple M is in the plane of the page and applied to member BF. Neglect friction on all mating parts. M 3 ft F 500 lb 3 ft CD 1 ft 4 ft Page 4 ft 2 of 5