Question

You pass by a building site and see a crane that lifts loads to upper floors of a building under construction. You wonder about the magnitude of the forces that support the beam of the crane. You snap a photograph of the crane with your smartphone. Back at home, you make a drawing of the crane from your photo. Your drawing is shown in the following figure. mg B 6 XCM You estimate the lengths d and l by measuring the distance between floors on a point of the building the same distance from your smartphone as the crane and using that distance as a scale for the drawing. This tells you that d = 1.00 m and l = 6.00 m. You have drawn the force vector for the gravitational force on the beam of the crane, but then you realize you don't know where the center of mass of the beam is located. You run back to the construction office and explain your interest. You ask the construction foreman about the crane, and he tells you that the crane itself has a mass of m, = 2,650 kg and the load it was lifting when you took the photograph has a mass of m, = 10,150 kg. You then ask the foreman about the location of the center of mass of the beam. Amused by your interest, he consults his documents and finds that the center of mass of the crane is located Xcm = 2.00 m horizontally to the right of point A. He also tells you that the pin at A is on a bearing and essentially frictionless, and the point B against which the crane pushes is smooth. Thanking the foreman and running home, you sit at your desk and determine the forces on the crane at points A and B. i + ÎN ÎN

Answer 1

m. a 2650 kg Me = 10150 leg sing 1 = 6M Efno RAXTRBx0 RAKE - RBX o EM so M. 92) + M2 g (6) - Pse ) 20 2650 (9.8) 2+10150 (9.8) 6- Rato Bu = 648760 N & ego RAR=-64876oN & Fy=0 Pay - м, 9 — ~59 ae Ray - 2650 (9.8) - 10150 (9.8) 20 RAG= 12544ON RA FA = Panit Ray ] =-6487 Go it 125440 J N F = Roeit oj = 6487 60 it oj N