I've done this with my sister, where we grab each other under the arms and heave, and we struggle and sweat, but nothing happens.

My thought is that I have to lift her weight + overcome the force of her pushing upwards off the ground, and I don't have it in me, but I'm struggling to understand exactly what's going on there.

Maybe I'll rig her up to a pulley system and see what happens.

The force of you trying to lift your sister is coutneracted by her trying to lift you up. Essentially, her force is trying to undo what you're doing.

Each of you applies a reaction force to the others' hands that pushes you both (via the pivot of your shoulders) back down into the floor – the overall net force vertically is 0.

If one of you could apply enough force to overcome both gravity and the others' muscles trying to pivot about their shoulder, one could lift the other, but never both.

Have you tried doing it one person at a time?

Just do the force diagrams and you will see why.

Can you pick up a chair you're sitting on?

They create stairway to heaven

I bet he's seen it on YouTube

They float, obviously. Same thing happens when you pull yourself up by your belt.

If you expect to hover, you need to say where the force is that’s lifting the combined “you-and-your-sister” object upwards. Hint: there isn’t one, which is why you can’t do it.

When you try to lift something you get heavier forcing yourself into the ground more. If they are doing the same you are both counteracting each other so no one goes anywhere

>You're trying to make yourself lower than her, she is trying to make herself lower than you.

Lowe’s.

As seen on TV