The figure shows a model of a crane that may be mounted on a truck.A rigid uniform horizontal bar of mass m_1 75.00 kg and length L 5.800 m is supported by two vertical massless stringsString A is attached at a distance d 2.000 m from the left end of the bar and is connected to the top plateString B is attached to the left end of the bar and is connected to the floorAn object of mass m_2 3500 kg is supported by the crane at a distance x 5.600 m from the left end of the bar.Throughout this problem, positive torque is counterclockwiseUse 9.81 m/s^2 for the magnitude of the acceleration due to gravity.1Find T_A, the tension in string A.2Find T_B, the magnitude of the tension in string B.
Since the bar is in equilibrium, the net force must be zero and the net torque must be zeroNet force 0 TA -TB - ( 75.00 kg ) g - ( 3500 kg ) ( g ) This gives us the relationship between the two tensions TA and TBNow for the torquesI'll arbitrarily select the left end of the bar as my originNow we have Net torque 0 -TA ( 2.000 m ) - TB ( 0 ) - ( 3500 kg ) ( g ) ( 5.600 m ) - ( 75.00 kg ) ( g ) ( 5.800 m / 2 ) You now have two equations in two unknowns, the tensions TA and TBSolve for those tensions.
