University:
Michigan State University
Course:
ERG 160 | Success in Science, Technology, Engineering, and Mathematics
Academic year:

2019
Views:

307

Pages:

1
Author:

Nossardisd7p

COSMOS: Complete Online Solutions Manual Organization System Chapter 8, Solution 54. Since vertical forces are equal and µ s ground > µ s wood, assume no impending motion of board. Then there will be impending slip at all wood/wood contacts, φ s = tan −1 µ s = tan −1 ( 0.35 ) = 19.2900° FBD Top wedge: R1 = 8 kN = 8.4758 kN cos19.29° R1 P = sin 52.710° cos 56.580° P = 8.892 kN To check assumption, consider FBD wedges + board: F1 = µ1 8 kN = 0.35 ( 8 kN ) = 2.8 kN ΣFy = 0: NG − 8 kN = 0, NG = 8 kN FG max = µG NG = ( 0.6 )( 8 kN ) = 4.8 kN ΣFx = 0: FG − F1 = 0, FG = F1 = 2.8 kN FG < FG max , OK ∴ P = 8.89 kN Vector Mechanics for Engineers: Statics and Dynamics, 8/e, Ferdinand P. Beer, E. Russell Johnston, Jr., Elliot R. Eisenberg, William E. Clausen, David Mazurek, Phillip J. Cornwell © 2007 The McGraw-Hill Companies.