Question

_{DETERMINE THE COMBINED MOMENT OF THE FOUR FORCES ACTING ON THE PULLEYS ABOUT THE AXIS AB (POINTS A AND B ARE THE CENTERS OF THE PULLEYS). 3 m 4 m 0.5 m -0.8 m 20 kN 60 KN 20 KN 40 KN WAT IS THE MOMENT OF THE FORCE ABOUT AXIS AB? (Unit: KN.m)}

Answer 1

.(0-3) +(4-0) +conoje û AB= (NGHA) i trys YA)j + (262) E MA= 20x0.5 i 60x0.5 i "direction either positive or let i, be unit vectors along x, y, 2 asis respectively The directions of moments at A & B can be found by right hand thumb rule * At A moment at A by the forces acting on Pulley att, MA negative be found by right hand thumb rule) -0 x' can am MA =-20 î KN- MA * At B m ܨܥܘ Moment at B by the forces acting on kulley at B, Me Mg = 40x0.8 ĵ - 20x0.8 j = 16 j kN * Coordinates of pont A & B ACMA, YA, 2A) = A(3,0,0);B[, 40,28)- 860,4,0) * Unit vector along AB Û AB -31 +42 (154A²+ (Y5YA) +(2520) (3) +(494 û AB 5 Combined moment about anis AB ,MAB of forces Mae = Ma. ûne + M. Une = (-202).(zatgj]+(67) Mas= 20x3 +1684 = 24.8 kw.m combined moment of forces about asas AB, MAB= 24.8 km Answer