Meriam, Kraige & Bolton — Equilibrium of Rigid Bodies: Problem 4_117

⚡ Mecademy AIENG정역학 · ch4 To solve the problem, we will analyze the equilibrium of the nose-wheel assembly by considering the geometry of the specific position and applying equilibrium equations to the individual components of the mechanism.  Problem Statement The nose-wheel assembly is raised by the application of a torque to link through the shaft at . If the arm and wheel have a combined weight of with center of gravity at , find the value of necessary to lift the wheel when is directly under , at which position angle is . Problem 4/117 (a) Calculation of the required torque 1. Formula: Equilibrium of arm : Equilibrium of link : Moment of a force: or , where is the perpendicular distance. 2. Substitution: Given values: weight , horizontal distance between and is , link lengths and , arm lengths and . In the specified position, and is directly under . We assume the center of gravity is at a distance from along the arm (based on standard problem data for this assembly). Define a coordinate system with at . Then is at . Coordinates of : . This confirms is directly under (). Coordinates of : . MBC BAO100 lb GMDB θ30 ∘ M ADOM =∑ A 0 BCM =∑ B 0 M = O r×FM=F⋅dd W=100 lbAB 16”L = BC 20”L = CD 20”L = AD 32” L = DO 8” θ=30 ∘ DB GAG=30”A A(0,0)B(16,0) DD=(32sin30,−32cos30)= ∘∘ (16,−27.71) in DBx = D x = B 16 GG=(30sin30,−30cos30)= ∘∘ (15,−25.98) in To find the position of , note that and . must lie on the horizontal perpendicular bisector of . The midpoint of is at . Horizontal dist