# Static Equilibrium Problem Dealing with Torque

by PeachBanana
Tags: dealing, equilibrium, static, torque
 P: 191 1. The problem statement, all variables and given/known data The figure shows a model of a crane that may be mounted on a truck. A rigid uniform horizontal bar of mass = 90.00 kg and length = 5.200 m is supported by two vertical massless strings. String A is attached at a distance = 1.600 m from the left end of the bar and is connected to the top plate. String B is attached to the left end of the bar and is connected to the floor. An object of mass = 3000 kg is supported by the crane at a distance = 5.000 kg from the left end of the bar. Throughout this problem, positive torque is counterclockwise and use 9.807 m/s^2 for the magnitude of the acceleration due to gravity. Find the tension in string A. 2. Relevant equations This problem lets you use hints and it suggested I use the following equation with having the Tension in String "B" as the origin. 3. The attempt at a solution Tension A(1.6000m) - (90.00 kg)(9.807 m/s^2) 1/2(5.200 m) - (3000 kg)(9.807 m/s^2)(5.000 m) = 0 I don't understand the "1/2" part in front of the length mass one. Is that because of where it is placed or its moment of inertia? Attached Thumbnails
 Sci Advisor HW Helper PF Gold P: 6,043 If the weight of the 90 kg beam is uniformly distributed over its length, where does its resultant load act?
 P: 191 I'm sorry, I'm not sure what you mean by resultant load.