Pry, Ramp and Hoist

Pry went first, sliding the long bar under the block — because a lever lets you push longer to lift heavier. "Put the block on my short end, and push down on my long end — way out here, far from the pivot." The girl pushed the long end down, a big sweeping push through a long arc — and the short end, moving only a tiny bit, heaved the great block up. "There. You just lifted something you couldn't budge. But notice the bargain: your end moved a long way down, and the block moved only a little way up. That's the whole trick. I let you use less force — but you apply it over a longer distance. Push far to lift near. You didn't get stronger; you spread your push out along my arm, and the spreading-out is what made the heavy thing light. Force times distance — the work — came out the same on both ends. That's why there's no free lunch, only a better arrangement."

Then Ramp leaned its long slope against the wall, because you can also trade distance for force by going the long way up. "You can't lift the block straight to the top of the wall — so don't. Roll it up me instead." The girl pushed the block up the long gentle slope — and it went, steadily, without the impossible strain of a straight lift. "See? Straight up would've been short but impossibly hard. Up my slope is long but easy. You did the same job — the block ended just as high — but you spread the effort along my whole length instead of cramming it into one impossible vertical heave." Ramp stretched proudly. "The gentler and longer I am, the easier the push — but the farther you travel. Same work, spread thin enough to fit your strength. A mountain road switchbacks for exactly this reason: the long way up is the only way a heavy thing gets up at all. That's mechanical advantage again — bought with distance."

And then Hoist dropped its rope from the wheel above, doing the same trick with a twist — redirecting the force so you can pull in the easy direction. "Here's mine. Loop the rope under the block, up over my wheel, and now — instead of lifting up, you pull down." The girl pulled down on her end, hanging her whole weight on it, and the block rose. "Pulling down is so much easier than lifting up — you can put your whole body into it. That's my first gift: I redirect the force to whatever direction suits you. And add more wheels, more loops of rope, and I do the lever's trick too: you pull a long length of rope with little force, and the block rises a short way with great force. Same bargain, dressed differently — more distance pulled, less force needed. I just let you pull it in the friendliest direction."