1. The problem statement, all variables and given/known data Hi guys, I am attempting to experimentally measure torque from two rods connected to a servo. Let's say rod A stays fixed, and the servo, mounted at the end of rod A (at joint J) moves rod B to a certain angle θ with a velocity v. In addition to velocity and angle, I also know that the servo is powered with a constant 5 volts, and in my measurement circuit I'm also measuring the current. Therefore I should know the instantaneous current (I) resulting from any force that opposes the movement of rod A. Also, let's say I can measure the mass and length of rod A, but I would prefer if I didn't have to do that. I hand-drew a picture to try and make this a bit more clear, but please let me know if I need to elaborate at all (I'm not very familiar with servos really, and physics isn't quite my thing). 2. Relevant equations I'm thinking I may need power, but a friend told me I may also need moment of inertia (let's call it IA). So I'm not quite sure, but I think these are important: P=IV IA=∑mr2 τ=rFsin(θ) 3. The attempt at a solution I was thinking that if I could obtain a profile for power, I could integrate to get the work, and somehow get torque from that. This is where I'm stuck though. I would really appreciate any help someone could provide me, even if it's just some direction. Is there something I'm not taking into account? What's the easiest way of doing this? Are there multiple ways?