when is net torque equal to 0?? Each of the four bars shown can rotate freely in the horizontal plane about its left end. For which diagrams is the net torque equal to zero? http://session.masteringphysics.com/problemAsset/1003642/26/170580B.jpg _____ i know that for torque to equal O angular momentum = I(omega) is constant and conserved... but i'm having trouble applying this to the diagram ... i thought D would be part of the answer because the Newtons all cancel out ... help??