1. The problem statement, all variables and given/known data In the image below, there are two balls of mass m attached to a massless rigid metal steam, which can rotate around the point A. Give the necessary velocity to be applied in the lowest ball for the system to reach the horizontal line. Do not consider any system's energy loss. 2. Relevant equations 3. The attempt at a solution I considered the center of the mass to be between the balls and established the following relationship: mv²/2 + mgj/2 = 2mgj v² = 3gj This being the velocity of the center of mass. However, the velocity of the center of mass is 3/4 of the velocity of the lowest ball (Vb), since the radius of center of mass is 3/4 the radius of the lowest ball. v = 3/4*Vb 3gj = 9/16*Vb² Vb = sqrt(16/3*gj) Which is wrong. Can someone please tell me what I'm doing wrong? Thanks!