Hey everyone. In my robotic engineering course, I have to build a hockey-puck hitting machine.

The motor we have has 0.5 lb*in of torque and its rotating motion is transmitted through gears all the way down to the hockey stick that needs to lift up to near 180 degrees before being released. My first instinct was to simply find the torque necessary by multiplying the mass of the stick by the distance between its center of mass and the axis of rotation. I end up with 6.3235 lb*in.

Then I would find the necessary gear ratio by dividing my torques and end up with 12.705 -> 13 gear ratio. Thing is, in the document for this setup, we have different values of inertia and I forgot to take them into consideration.

Where does inertia come into play here? Surely it would affect the torque needed to get moving in the first place.