[Mentor's Note: Thread moved from the technical forums after receiving replies] I'm just learning torque, but if I went wrong here can someone help me (or explain the textbook explanation better). My work was: Torque=.4m(weight of 5kg)sin(120) which comes out to 1.73 The answer choices are A=.49 B=.98 C=1.7 D=2 E=3.4 The answer is D, and it is apparently because "from the diagram, sin(theta)=40cm/L, so Lsin(theta)=40cm. That is, the question gave the lever arm already. (The given angle of 60 degrees is irrelevant.) Thus, from Torque=Fl, the torque is (.4m)(.5kg)(10m/s^2)=2." Why doesn't Torque=rFsin(theta) apply? Why is the angle irrelevant? Thank you to all who reply; this is my first post so if I make any mistakes I apologize.