Feedback Weight in unity

Create a "weight" with a Cube scaled on the Z=15 axis, on the HingeJoint in the middle and on the right side: 3 Cubes with mass 4 as rigid bodies (Z=3), and on the left: (Z=-6) one Cube with ConstantForce component. How much force should be applied to keep the scale in balance? Provide the result as an absolute value with a precision of unity. (Force Y value in the ConstantForce component). I have this problem, and i seem to cant figure i out. I have tried every number of forces to keep it in balance but it always end with something like this:

- link to the video showing all my settings

Thank you for your help in advance!

 

That is not a scale, it’s a seesaw. As you’ve probably noticed, it does not compare two weights. If a grownup sits close to the hinge, and a child is far from the hinge, the seesaw can be in equilibrium. To be more accurate, the seesaw is in equilibrium when the torque around the hinge is zero. You can calculate the torque by multiplying the distance from the hinge by the mass and gravity.

That boils down to:
Sum over (Mass * G * distance) = 0

To actually answer your question, there are two routes: either make it an actual scale by hanging two “plates” on both sides with equal distance from the hinge. If you place the cubes on the plates, the scale will work and if there are cubes with a total weight of 16 on one side and a cube with weight 1 on the other side, you’ll have add a constant force of 15*gravity (15*9.81) on the single cube.

Or you can go the other route and create a torque equilibrium. Tell us more about what you’re actually trying to achieve, then it’s a easier to help you.