Meriam, Kraige & Bolton — Statics of Particles: Problem 2_37

⚡ Mecademy AIENG정역학 · ch2  Problem Statement 2/37 A 150-N pull is applied to a cord, which is wound securely around the inner hub of the drum. Determine the moment of about the drum center . At what angle should be applied so that the moment about the contact point is zero? Problem 2/37 (a) Moment of about the drum center ● Calculation Process 1. Present Final Formula: Since the cord is wound around the inner hub, the line of action of the pull is always tangent to the hub. The perpendicular distance from the center to the line of action is therefore equal to the radius of the inner hub, . 2. Substitute Values: Given and . 3. Final Calculation: Observing the direction of pull in the diagram, it creates a counter-clockwise (CCW) rotation about point . ● Final Conclusion: The moment of force about the drum center is in the counter-clockwise direction. (b) Angle for zero moment about point ● Calculation Process 1. Present Final Formula: For the moment about the contact point to be zero ( ), the line of action of the force must pass directly through point . Since is tangent to the inner hub, it forms a right triangle where is the point of tangency. In this right triangle, the hypotenuse is the distance between centers, , and the T TCθT P TC TC r i M = C T⋅r i T=150Nr = i 125mm=0.125m M = C 150⋅0.125 M = C 18.75N⋅m T C TC18.75N⋅m θP PM = P 0TPT CPQQ CP=r o side adjacent to the angle at is the inner radius, . Let be the angle . From the geometry of the right triangle: From geometr