Levers: lifting heavy things with a little push

Tests: 5 of 11 right · Exam: 2 of 4 right · Kind: plain · Understood: 7 of 15 · Run: 2026-10-18, commit f3c23ea72

Lesson 33 of the physics course of Mova's primary school, as Mova's small model took its tests: it had read this lesson and the ones before it and learned from their exercises. Each test shows the options in the order the student saw them, its choice, the right answer, the score of every option and why it chose. The lesson itself, sentence by sentence with trees and pragmatics: the lesson in the corpora.

Every question of this lesson and each of its options parsed by Mova, with trees and pragmatics: the lesson's questions in the corpora.

Test 1 · wrong ✗

mate says levers are magic, you get something for free. right?

1. Yes, levers make energy out of nothing — no support
2. No, you push less, but you have to push further — ✓ the right answer · no support
3. No, levers only make things harder to lift — ← Mova's choice · score 4
4. Yes, a lever doubles your strength and your speed — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 4, the only option with support. Its support: lesson 33, line 4: «Levers can also swap the other way, giving up force for speed and reach, which is how your arm and a fishing rod flick things far and fast.», reached through the option's own match among the sentences about the question's things. What matched: the same thing acted on «other way» (+3); the same doer «levers» (+2). Against it: a different action (counts against) (-1). The right option, 2, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 2 · wrong ✗

Your big brother sits on the seesaw and you can't lift him. What should you do?

1. Take your shoes off — no support
2. Push down more gently — no support
3. Ask him to move closer to the middle — ✓ the right answer · score 4
4. Sit closer to the middle yourself so you are nearer the pivot — ← Mova's choice · score 8

Why: It took the question to ask what is done. It chose option 4 with score 8, against 4 for the next best. Its support: lesson 33, line 8: «A seesaw is a lever with the pivot in the middle, so a child sitting far out can lift a grown-up sitting close in.», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+5); the same action «sit» (+3). The right option, 3, scored 4. · the question and its options parsed, with trees and pragmatics

Test 3 · wrong ✗

Leo tries to cut a thick cereal box with the tips of the scissors. What tip would you give him?

1. Turn the scissors upside down — ← Mova's choice · no support
2. Use the very tips of the blades and press much harder — no support
3. Slide the card deep in, near the hinge — ✓ the right answer · no support
4. Cut faster so it does not notice — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 4 · right ✓

In a cartoon, a mouse lifts an elephant with a tiny short plank. What would really be needed?

1. A very long plank with the pivot near the elephant — ← Mova's choice · ✓ the right answer · no support
2. A thicker plank with the pivot near the mouse — no support
3. Nothing more, any plank will do — no support
4. A plank made of steel instead — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 5 · wrong ✗

oi, stop loading all the bricks at the handle end of the wheelbarrow, you muppet. why?

1. The wheel will burst under bricks — ← Mova's choice · no support
2. Bricks at the wheel end will make the tyre burst flat — no support
3. The handles are made for bricks — no support
4. The load is easier to lift close to the wheel — ✓ the right answer · no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 6 · right ✓

How could ancient people move giant stones without machines?

1. They melted and re-poured them — no support
2. With levers and ramps — ← Mova's choice · ✓ the right answer · score 11
3. They carried them on their heads — score 3
4. They were much stronger than us — no support

Why: It took the question to ask what something is like. It chose option 2 with score 11, against 3 for the next best. Its support: lesson 33, line 13: «A crowbar with a small stone underneath as a pivot can lift a heavy stone slab; ancient builders moved giant stones with levers and ramps.», reached through the remembered sentence the question matched. What matched: the same action «move» (+5); the same circumstance (+4); the same thing acted on «giant stones» (+3). Against it: a different doer (counts against) (-1). · the question and its options parsed, with trees and pragmatics

Test 7 · right ✓

Your hand is far from the elbow, but your muscle is fixed close to it. What does that mean?

1. The muscle pulls hard, and your hand moves fast — ← Mova's choice · ✓ the right answer · score 6
2. The muscle does not need to work at all — score 1
3. Your hand pushes the muscle along — score 3
4. The muscle pulls gently, and your hand moves slowly — score 6

Why: It took the question to ask what it is done to. It chose option 1 with score 6, tied with another option at 6 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 33, line 14: «Your arm is a lever with the elbow as the pivot; the muscle pulls close to the elbow, so it must pull hard, but the hand moves far and fast.», reached through the remembered sentence the question matched. What matched: the same action «move» (+3); the same doer «hand» (+3). · the question and its options parsed, with trees and pragmatics

Test 8 · right ✓

Why would it be silly to lift a heavy stone with tweezers?

1. Stones are magnetic and stick to them — no support
2. Tweezers only work on wood — no support
3. Tweezers give less force, not more — ← Mova's choice · ✓ the right answer · score 5
4. Tweezers are too long and too strong — no support

Why: It took the question to ask why something happens (its cause). It chose option 3 with score 5, the only option with support. Its support: lesson 33, line 15: «Tongs and tweezers are levers pressed in the middle; they give less force but more control, so they suit careful work.», reached through the same lesson line as the sentence the question matched. What matched: the same action «give» (+4); the same thing acted on «less force» (+2). Against it: a different doer (counts against) (-1). · the question and its options parsed, with trees and pragmatics

Test 9 · wrong ✗

Dad gets a short screwdriver and a long one to open a stuck tin. Which should he pick?

1. Neither, levers do not help with tins — ← Mova's choice · no support
2. Either, length does not matter — no support
3. The short one — no support
4. The long one — ✓ the right answer · no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 10 · right ✓

What would happen if you put the walnut at the far end of the nutcracker handles?

1. It would be much harder to crack — ← Mova's choice · ✓ the right answer · no support
2. Nothing would change — no support
3. It would crack much more easily — no support
4. It would fly out and crack by itself — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 11 · wrong ✗

Why can a tennis racket send the ball so fast?

1. It works like a long arm, turning small wrist moves into big fast ones — ✓ the right answer · no support
2. It is heavier than the ball — ← Mova's choice · score 5
3. Its strings are magnetic — no support
4. It is full of springs that push the ball — no support

Why: It took the question to ask why something happens (its cause). It chose option 2 with score 5, the only option with support. Its support: lesson 4, line 4: «Forces come in pairs: stand on a skateboard and throw a heavy ball forward, and the ball pushes you backwards just as hard.», reached through the option's own match among the sentences about the question's things. What matched: the same circumstance (+3); the same property (+2). The right option, 1, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Exam question 1 · formal language · right ✓

Identify the fixed point about which a lever rotates.

1. The pivot — ← Mova's choice · ✓ the right answer · no support
2. The load — no support
3. The effort — no support
4. The handle — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Exam question 2 · formal language · wrong ✗

Ascertain the position in which a load ought to be placed in a wheelbarrow so as to minimise the effort required.

1. In close proximity to the handles — ← Mova's choice · no support
2. Overhanging the rear of the barrow — no support
3. In close proximity to the wheel — ✓ the right answer · no support
4. The position is immaterial to the effort — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Exam question 3 · formal language · right ✓

Which of the following statements most accurately characterises the operation of a lever employed to raise a heavy object?

1. The lever reduces the weight of the object itself — no support
2. A small force applied far from the pivot yields a greater force near it — ← Mova's choice · ✓ the right answer · score 6
3. The lever creates additional energy for the user — no support
4. A large force applied near the pivot yields a smaller force far from it — score 6

Why: It took the question to ask who or what does it. It chose option 2 with score 6, tied with another option at 6 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 33, line 6: «A lever is a stiff bar that turns about a pivot, and a small force far from the pivot makes a big force near it.», reached through the option's own match among the sentences about the question's things. What matched: it fills the role the question asks for (+3); the same doer «small force» (+2); the same thing acted on «big force» (+2). Against it: a different action (counts against) (-1). · the question and its options parsed, with trees and pragmatics

Exam question 4 · formal language · wrong ✗

Select the response consistent with the established facts concerning the human forearm.

1. It constitutes a pulley, the wrist serving as its wheel — ← Mova's choice · no support
2. It constitutes a lever, the elbow serving as its pivot — ✓ the right answer · no support
3. It constitutes a screw, the shoulder serving as its thread — no support
4. It operates by no mechanical principle whatsoever — no support

Why: Nothing it remembers matched the question, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

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