Rockets, record speeds and motion everywhere

Tests: 6 of 12 right · Exam: 2 of 4 right · Kind: ★★★ · Understood: 14 of 16 · Run: 2026-10-18, commit f3c23ea72

Lesson 38 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 · ★★★ · right ✓

lol my mate says rockets can't work in space cos there's no air to push on. is he right?

1. Yes, they glide in space with no engines ever — no support
2. No, space is full of air — score 3
3. Yes, rockets stop once they leave the air — no support
4. No, the rocket pushes its own gas out and the gas pushes back — ← Mova's choice · ✓ the right answer · score 6

Why: It took the question to ask which statement is true. It chose option 4 with score 6, against 3 for the next best. Its support: lesson 38, line 6: «A rocket throws hot gas out downwards and the gas pushes the rocket up; it does not need air to push against.», reached through the option's own match among the sentences about the question's things. What matched: the same thing acted on «hot gas» (+4); the same doer «rocket» (+3). Against it: a different action (counts against) (-1). · the question and its options parsed, with trees and pragmatics

Test 2 · ★★★ · right ✓

In a cartoon, a rocket orbits the Earth slowly, just faster than a car. What's wrong?

1. It would need to go about 28,000 kilometres an hour or it would fall — ← Mova's choice · ✓ the right answer · score 7
2. It would float away from the Earth — score 4
3. It would orbit even if it stopped — no support
4. Nothing, rockets orbit slowly — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 7, against 4 for the next best. Its support: lesson 38, line 8: «To circle the Earth, a rocket must move at about 28,000 kilometres an hour sideways; at that speed it falls round the Earth instead of back down.», reached through the option's own match among the sentences about the question's things. What matched: the same action «fall» (+4); the same doer «rocket» (+3). · the question and its options parsed, with trees and pragmatics

Test 3 · ★★★ · wrong ✗

Grandpa's sitting in his armchair "doing nothing". How fast is he really moving through space?

1. About 900 kilometres an hour — ← Mova's choice · score 6
2. Not at all, he's sitting perfectly still in his chair — score 0
3. About 40 kilometres an hour — score 6
4. About 100,000 kilometres an hour round the Sun — ✓ the right answer · no support

Why: It took the question to ask what something is like. 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 38, line 8: «To circle the Earth, a rocket must move at about 28,000 kilometres an hour sideways; at that speed it falls round the Earth instead of back down.», reached through the remembered sentence the question matched. What matched: the same circumstance (+4); the same action «move» (+3). Against it: a different doer (counts against) (-1). The right option, 4, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 4 · ★★★ · wrong ✗

If you stood on a skateboard and threw a heavy ball forward, then switched to throwing it backward, what would change?

1. You would roll forward both times, whichever way you threw — ← Mova's choice · no support
2. You would roll the opposite way each time — ✓ the right answer · no support
3. You would stay still both times — no support
4. You would roll sideways — 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 · ★★★ · right ✓

shut up and hold the hose properly, it's flapping everywhere!! why does it even do that

1. The tap is broken — no support
2. The wind is blowing it about because it is so light — no support
3. The water rushing out pushes the hose back — ← Mova's choice · ✓ the right answer · score 7
4. The hose is alive — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 7, the only option with support. Its support: lesson 38, line 11: «A hose pushes back when water rushes out of it, so firefighters must hold big hoses together.», reached through a sentence linked to the one the question matched. What matched: the same action «rush out» (+4); the same doer «water» (+3). · the question and its options parsed, with trees and pragmatics

Test 6 · ★★★ · right ✓

In the car, Mum brakes; your backpack slides forward but your helium balloon leans back. Why the difference?

1. Balloons always move the opposite way to everything — no support
2. The balloon is heavier than the backpack, so it moves less — no support
3. The air sloshes forward and pushes the light balloon back — ← Mova's choice · ✓ the right answer · score 11
4. The balloon is scared of the windscreen — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 11, the only option with support. Its support: lesson 38, line 16: «In a braking car a helium balloon on a string leans backwards, because the heavier air sloshes forward and pushes the light balloon away, as water pushes a cor…», reached through the option's own match among the sentences about the question's things. What matched: the same action «push» (+4); the same thing acted on «light balloon» (+4); the same doer «heavier air» (+3). · the question and its options parsed, with trees and pragmatics

Test 7 · ★★★ · wrong ✗

What would a curling stone do on rough, bumpy ice?

1. Slide even further — ← Mova's choice · score 12
2. Stop very soon — ✓ the right answer · no support
3. Fly up into the air — no support
4. Spin faster and faster — no support

Why: It took the question to ask what is done. It chose option 1 with score 12, the only option with support. Its support: lesson 38, line 17: «A curling stone slides far because smooth ice has very little friction, and the sweepers smooth and warm the ice to make it glide further.», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+5); the same doer «curling stone» (+4); the same action «slide» (+3). The right option, 2, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 8 · ★★★ · wrong ✗

Why might a satellite need to be launched from near the equator, where the ground spins fastest?

1. Gravity is switched off at the equator, so lifting is easy — no support
2. The Earth's spin gives it a free sideways start — ✓ the right answer · score 3
3. The Moon helps pull it up — score 2
4. The air is thinner there — ← Mova's choice · score 4

Why: It took the question to ask which statement is true. It chose option 4 with score 4, against 3 for the next best. Its support: lesson 14, line 15: «High above the ground the air is thin and presses less; down low it presses harder, so a sealed crisp packet carried up a high mountain puffs up like a pillow.», reached through the option's own match among the sentences about the question's things. What matched: the same doer «air» (+3); the same light verb (be, have, do, get, go) (+1). The right option, 2, scored 3. · the question and its options parsed, with trees and pragmatics

Test 9 · ★★★ · wrong ✗

Lila says an octopus swims just like a rocket. Is she right?

1. No, rockets push on the air, but octopuses push on the sand — ← Mova's choice · score 7
2. Yes, octopuses burn fuel — no support
3. Yes, it pushes water out one way and moves the other way — ✓ the right answer · score 7
4. No, octopuses only crawl — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 7, tied with another option at 7 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 4, line 17: «Rockets work in the same way, pushing hot gas out of the back so that the gas pushes them forward.», reached through the option's own match among the sentences about the question's things. What matched: the same action «push» (+4); the same doer «rockets» (+3). The right option, 3, scored 7. · the question and its options parsed, with trees and pragmatics

Test 10 · ★★★ · right ✓

A rocket is mostly fuel. What happens to the empty fuel tanks?

1. They are kept to the end — no support
2. Stages drop away as they empty — ← Mova's choice · ✓ the right answer · score 3
3. The astronauts throw them out of the window — no support
4. They turn into new fuel — no support

Why: It took the question to ask which statement is true. It chose option 2 with score 3, the only option with support. Its support: lesson 38, line 9: «Most of a rocket is fuel, and its stages drop away as they empty.», reached through the same lesson line as the sentence the question matched. What matched: the same action «drop away» (+1); the same doer «stages» (+1); the same property (+1). · the question and its options parsed, with trees and pragmatics

Test 11 · ★★★ · wrong ✗

Which needs the biggest push back to manage: a garden hose, a fire hose or a drinking straw?

1. All exactly the same — ← Mova's choice · score 3
2. A fire hose — ✓ the right answer · score 3
3. A garden hose — score 3
4. A drinking straw — score 3

Why: It took the question to ask who or what does it. It chose option 1 with score 3, tied with another option at 3 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 36, line 17: «To turn, you need a sideways push from the ground on your feet, which is why footballers slip turning on wet grass.», reached through the option's own match among the sentences about the question's things. What matched: the same action «need» (+2); the same thing acted on «sideways push» (+2). Against it: a different doer (counts against) (-1). The right option, 2, scored 3. · the question and its options parsed, with trees and pragmatics

Test 12 · ★★★ · right ✓

You push your skateboard once on a smooth path and it rolls for ages; on gravel it stops at once. Why?

1. Gravel is always uphill — no support
2. On gravel the small wheels catch on stones and friction grows — ← Mova's choice · ✓ the right answer · score 5
3. The smooth path pushes the board along — no support
4. Gravel pulls the board down with magnets — 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 38, line 18: «Skateboard wheels and bearings have little friction, so a smooth path keeps you rolling, but small wheels catch on gravel, and wrist guards and helmets protect…», reached through the option's own match among the sentences about the question's things. What matched: the same action «catch» (+2); the same place «gravel» (+2); the same doer «small wheels» (+1). · the question and its options parsed, with trees and pragmatics

Exam question 1 · formal language · right ✓

Identify the principle by which a rocket is propelled in the absence of an atmosphere.

1. The rocket is drawn upward by the gravity of the Moon — no support
2. Gas expelled in one direction exerts an equal push upon the rocket in the opposite direction — ← Mova's choice · ✓ the right answer · score 8
3. The rocket is borne aloft by the solar wind — no support
4. The rocket pushes against the surrounding air — score 7

Why: It took the question to ask which statement is true. It chose option 2 with score 8, against 7 for the next best. Its support: lesson 38, line 6: «A rocket throws hot gas out downwards and the gas pushes the rocket up; it does not need air to push against.», reached through the option's own match among the sentences about the question's things. What matched: the same action «throw out» (+4); the same thing acted on «hot gas» (+4). · the question and its options parsed, with trees and pragmatics

Exam question 2 · formal language · right ✓

Ascertain the reason for which a satellite in orbit does not descend to the Earth.

1. Gravitation ceases entirely beyond the atmosphere — no support
2. It is suspended by the pressure of sunlight alone — no support
3. Its engines operate without any interruption so as to hold it above the Earth — no support
4. Its sideways velocity is such that it continually falls around the Earth — ← Mova's choice · ✓ the right answer · score 6

Why: It took the question to ask which statement is true. It chose option 4 with score 6, the only option with support. Its support: lesson 38, line 3: «To stay in orbit a rocket must go about 28,000 kilometres an hour sideways, so fast that it keeps falling round the Earth instead of back down to it.», reached through the option's own match among the sentences about the question's things. What matched: the same action «fall» (+4); the same place «earth» (+2). · the question and its options parsed, with trees and pragmatics

Exam question 3 · formal language · wrong ✗

Which of the following statements most accurately characterises the motion of a person seated at rest upon the Earth?

1. The person is borne round the Sun at approximately one hundred thousand kilometres per hour — ✓ the right answer · score 4
2. The person moves solely when walking — score 8
3. The person is wholly at rest in every respect — ← Mova's choice · score 10
4. The person moves at approximately forty kilometres per hour — score 8

Why: It took the question to ask who or what does it. It chose option 3 with score 10, against 8 for the next best. Its support: lesson 13, line 4: «Knowing how water behaves keeps people safe: thin ice, rip currents and a person quietly struggling in the water are real dangers, and the safe move is always…», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+5); the same doer «thin ice» (+3); the same light verb (be, have, do, get, go) (+2). The right option, 1, scored 4. · 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 propulsion of a squid.

1. It is propelled by the combustion of stored fat — ← Mova's choice · no support
2. It is propelled through the water by the rapid beating of its numerous legs — no support
3. It is carried exclusively by the currents — no support
4. It expels a jet of water and is thereby driven in the opposite direction — ✓ 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

This page in Markdown → https://md.mova.elamur.ai/free/en/school-run/physics/38-rockets-record-speeds-and-motion-everywhere/