These hooks were made for the IKEA JONAXEL product family of shelves.
There are two main categories: HEAVY-DUTY(only attachable to the frame) and LIGHT-DUTY (attachable to either frame or the shelves). Examples:

The hooks come with these dimensions:
As for science, the smallest light duty version will top out at 5 bananas, any more bananas and the hook will fall down (I caught the bananas).

The heavy duty version can easily handle 10 bananas, but unfortunately I ran out of bananas to properly test it to failure. By my estimation as experienced banana user, it will easily hold at least 40 bananas before hook might slip slightly but still hang on, and probably around 70 bananas until it completely loses grip.

I've included a .STEP file with proper polysurface geometry so you can adjust them to your needs.
The author marked this model as their own original creation.