A turnbuckle, similar to that shown in Fig., is used to tension member AB of the truss. Th...

A turnbuckle, similar to that shown in Fig., is used to tension member AB of the truss. The coefficient of the static friction between the square-threaded screws and the turnbuckle is μs = 0.5. The screws have a mean radius of 6 mm and a lead of 3 mm. Determine the torque M which must be applied to the turnbuckle to draw the screws closer together, so that the compressive force of 500 N is developed in member BC.

Figure