ENGG 202 Lecture Notes - Lecture 1: Bulldozer
26 Jan 2015
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Frames and machines: the 80 kg ventilation door od with mass center at g is held in the equilibrium position shown (open) by means of a moment m applied at a to the linkage mechanism. Ab is parallel to the door for the 30 position shown. All joints are pin connections: determine the forces acting on member ocgd at o and c, determine m. Ans: cb=840. 9 n (c), ox= -528. 6n, oy=130. 8n, m = 706. 3 nm. Solution strategy: a) draw the fbd of the gate ocgd, there will be 3 unknowns (2 at o and cb is a 2 force member), write 3 eqns of equil to solve for these unknowns. You will need to apply some knowledge of geometry to find the angle of member cb. Determine the horizontal and vertical reactions at pin c if the blocks are pressed together with a vertical normal force of 200 n. Ans: cx = 500 n, cy = -200 n (on abc)
