Hi, I will keep this short and sweet. I am drop testing an object of complicated geometry froma set height in 10 different orientations. Due to the complexity I decided to make a free falling rig where it slides (via roller bearings for example) when released. Simple freefall analysis using energy equation from dropping it at a set height h: mgh=1/2m(v^2) v = √2gh Falling attached on the rig: Mgh - Fh = 1/2M(v^2) where M is mass including the attachment and arm. and -Fh is friction energy lost from the bearing rolling/sliding down the rig. (i want to keep it within 2% of freefall velocity so will need to find a coefficent of friction which allows this) However we can see the mass doesn't effect the velocity, doesn't the mass change the force/energy it hits the ground with? Hence: mgh(freefall) = mgh(rig) So solving for the height will give me the height at which the object will hit the floor with the same energy/force. Is this right? Due to terminal velocity, would I need to solve for this as well ? Thanks. I have attached a diagram to help.