Using Torque Choose the rotation axis to be along the z direction (out of the page )through the cm: The torque due to the string T1 T2 on the right about this axis is cm M L2 14 The torque due to the string on the left about this axis is Mg Gravity exerts no torque about CM Physics 121: Lecture 17, Pg 9Physics 121: Lecture 17, Pg 9 Using Torque... Choose the rotation axis to be along the z direction (out of the page) through the CM: L/2 L/4 x cm M T1 T2 Mg y x  2 2 4 =T L The torque due to the string on the right about this axis is: 1 1 2 = −T L The torque due to the string on the left about this axis is: Gravity exerts no torque about CM