Pushes and pulls: what makes things move and stop
Tests: 6 of 11 right · Exam: 0 of 4 right · Kind: plain · Understood: 4 of 15 · Run: 2026-10-18, commit f3c23ea72
Lesson 4 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 ✗
My mate says things just stop on their own when they run out of push. right?
- 1. Yes, things get tired — ← Mova's choice · no support
- 2. No, something always pushes against them — ✓ the right answer · no support
- 3. No, things speed up on their own — no support
- 4. Yes, every push runs out in time and then stops — 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 2 · wrong ✗
In a cartoon a man stands in a rowing boat and blows into its sail to move it. What is wrong?
- 1. Boats only move with engines — ← Mova's choice · no support
- 2. His breath pushes the boat back, so it barely moves — ✓ the right answer · no support
- 3. Breath is too warm to push — no support
- 4. Nothing, it works perfectly — 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 3 · right ✓
You tape a balloon to a straw on a string and let it go. What happens?
- 1. It zooms along the string like a little rocket — ← Mova's choice · ✓ the right answer · score 4
- 2. It floats up off the string — score 4
- 3. It slides straight back towards you along the string — score 4
- 4. It stays still on the string — score 4
Why: It took the question to ask what happens next. It chose option 1 with score 4, tied with another option at 4 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 4, line 16: «A balloon let go without its knot squeezes air out of its neck, and the air rushing out pushes the balloon the other way.», reached through what followed the sentence the question matched. What matched: the same doer «balloon» (+4). · the question and its options parsed, with trees and pragmatics
Test 4 · right ✓
shut up and push the trolley, it's full, why's it so hard to stop on the ramp?
- 1. The wheels are stuck — no support
- 2. Gravity stops on ramps — no support
- 3. Ramps make trolleys heavier the further down they go — no support
- 4. More stuff in it means it is harder to stop — ← Mova's choice · ✓ the right answer · score 4
Why: It took the question to ask why something happens (its cause). It chose option 4 with score 4, the only option with support. Its support: lesson 4, line 13: «The more mass something has, the harder it is to start, stop or turn, so a full trolley is harder to push and to stop than an empty one.», reached through a sentence linked to the one the question matched. What matched: the same action «stop» (+2); the same doer «full trolley» (+2). · the question and its options parsed, with trees and pragmatics
Test 5 · wrong ✗
What would happen to a book on a table if the table were taken away?
- 1. It would stay because books have no weight — ← Mova's choice · score 4
- 2. It would fall, with only gravity left — ✓ the right answer · score 2
- 3. It would slowly drift up — score 2
- 4. It would stay floating in the air — score 2
Why: It took the question to ask what happens next. It chose option 1 with score 4, against 2 for the next best. Its support: lesson 4, line 11: «A book on a table stays put because gravity pulls it down and the table, squashed a tiny bit like a very stiff spring, pushes it up just as hard.», reached through what followed the sentence the question matched. What matched: the same doer «book» (+4). The right option, 2, scored 2. · the question and its options parsed, with trees and pragmatics
Test 6 · right ✓
An astronaut in space throws a spanner away. What happens to him?
- 1. He moves slowly the other way — ← Mova's choice · ✓ the right answer · no support
- 2. He spins round and round on the spot — no support
- 3. He moves off after the spanner — no support
- 4. He stays perfectly still where he is — 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 7 · wrong ✗
Which uses the same idea as a rocket?
- 1. A ball rolling slowly down a grassy hill — ← Mova's choice · no support
- 2. A book lying quite still on a shelf — no support
- 3. A balloon whizzing round the room — ✓ the right answer · no support
- 4. A leaf drifting down from a tall tree — 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 8 · right ✓
A football player kicks softly, then hard. Which is true?
- 1. The harder kick makes a faster ball — ← Mova's choice · ✓ the right answer · no support
- 2. Kicks do not change the speed — no support
- 3. Both kicks make the same speed — no support
- 4. The softer kick makes a faster ball — 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 9 · right ✓
Why should you step off a small boat carefully, with a hand on the jetty?
- 1. Your push can send the boat away and you into the water — ← Mova's choice · ✓ the right answer · no support
- 2. The jetty pushes you back — no support
- 3. Jetties are always slippery — no support
- 4. Boats sink when you stand up — 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 · wrong ✗
Two equal teams pull a rope and it does not move. Is there no force at all?
- 1. The ground under them cancels the forces out — ← Mova's choice · no support
- 2. There are big forces, but they cancel — ✓ the right answer · no support
- 3. Yes, there is no force on the rope at all — no support
- 4. Only the rope itself has any force in it — 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 · right ✓
In a game a car stops dead the moment you let go of the button, even on ice. Is that real?
- 1. No, on ice it would slide on a long way — ← Mova's choice · ✓ the right answer · no support
- 2. Yes, cars always stop at once — no support
- 3. No, it would speed up on ice — no support
- 4. Yes, ice stops cars fastest of all surfaces — 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 1 · formal language · wrong ✗
Which of the following statements most accurately characterises the cause of the cessation of motion in a rolling ball?
- 1. The ball ceases to move after a fixed interval — ← Mova's choice · score 4
- 2. The ball exhausts an internal store of motion — score 4
- 3. The gravitational attraction acts horizontally against it — no support
- 4. Forces exerted by the ground and the air act in opposition to its motion — ✓ the right answer · no support
Why: It took the question to ask who or what does it. It chose option 1 with score 4, tied with another option at 4 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 4, line 3: «Nothing stops "by itself": a rolling ball slows down because the grass and the air keep pushing against it a little.», reached through the same lesson line as the sentence the question matched. What matched: it fills the role the question asks for (+3); the same doer «rolling ball» (+2). Against it: a different action (counts against) (-1). The right option, 4, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics
Exam question 2 · formal language · wrong ✗
It is given that two teams in a tug of war exert equal and opposite forces upon a rope. Determine the consequence for the motion of the rope.
- 1. The rope moves towards the weaker team — ← Mova's choice · no support
- 2. The rope moves towards the stronger team — no support
- 3. The rope remains at rest — ✓ the right answer · no support
- 4. The rope is accelerated upwards — 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 · wrong ✗
Identify the principal reason for which a person standing upon a skateboard moves backwards upon throwing a heavy ball forwards.
- 1. The ground exerts a horizontal force towards the rear — ← Mova's choice · no support
- 2. The air in front of the person is compressed — no support
- 3. The ball exerts upon the person a force equal and opposite to that applied — ✓ the right answer · no support
- 4. The skateboard possesses a motion of its own — 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 4 · formal language · wrong ✗
Select the response that is consistent with the established facts concerning a laden trolley.
- 1. Its mass has no bearing upon the force required — ← Mova's choice · no support
- 2. Its greater mass causes it to move of its own accord — no support
- 3. Its greater mass renders it more difficult both to start and to arrest — ✓ the right answer · no support
- 4. Its greater mass renders it more easily arrested — 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
This page in Markdown → https://md.mova.elamur.ai/free/en/school-run/physics/4-pushes-and-pulls-move-and-stop/