Question

There is friction between blocks A B 160 F Surface with friction Two blocks labeled A and B are initially placed in contact as shown in the figure. The masses of the blocks are ma = 15.4 kg and mb = 3.6 kg. There is friction between A and the ground. There is also friction between the two blocks. The coefficient of kinetic friction between A and the ground is jk = 0.33. The coefficient of static friction between the two blocks is js = 0.65. The system is subject to the regular force of gravity (g = 9.80665 m/s2). If the system is at rest, B falls down. However, if a force Ě of sufficient magnitude is applied to A towards the right as shown in the figure, the whole system accelerates to the right and B does not fall. (a) Determine the minimum magnitude of the force F so that B does not fall. Instructions -

Answer 1

Solution in the uploaded images

Solution. MN MA- 15.4ing mo = 36 kg A fo MK = 0.33 Ms= 0.65 ing reaking FBD muutons law using F = (ma+mexa a= 등 15.4+ 3.6 19 Torce codasees on B = B.6x9 3.6xF 19 - Normal force, N= 3. 6xF 19 (a les x N = mox moxg 36x9.8 0.65x 36 x Frin 19 Fnin = 286.46 N (6) Friction Jorce = 4sxN 0.65 3.6x286.46 19 = 0d 35.28N (c) Not forec on B, N= 3.6 x 28646 14 54.28N

(d) when F = 2 x Fnin Normel force, N- 3.6x2x2 86.46 19 108.6N Friction force Msx N 0.65xRot 108.6 - 70.56N understood # hit like if you