---
title: Which is true about friction? — Forces — pushes, pulls, friction and m… · tree and pragmatics
description: Which is true about friction? Test 5 of lesson 51 «Forces — pushes, pulls, friction and magnets» of the world course of Mova's primary school, with the dependency tree and pragmatics of the question and of each option; Mova's choice was right.
---

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# Test 5 · Forces — pushes, pulls, friction and magnets

<!-- .ven lang=en -->
Which is true about friction?

<!-- .vintro -->
**Mova's choice:** option 4 · **The right answer:** option 4 · right ✓ · **What happens:** be

<!-- .vabout -->
This is test 5 of lesson 51 «Forces — pushes, pulls, friction and magnets» of the world course of Mova's primary school. The page gives the question's syntax tree — a dependency tree in the style of Universal Dependencies — and its pragmatics clause by clause, then the 4 options as the student saw them, each with its tree and pragmatics. Every text is parsed by Mova itself. How the student answered it, with the score of every option and why: [the test at school](https://md.mova.elamur.ai/free/en/school-run/world/51-forces/#t5).

## The question {#question}

```conllu
# sent_id = question:world:51-forces:t5:1
# text = Which is true about friction?
1	Which	which	PRON	WDT	PronType=Rel	3	nsubj	_	_
2	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	3	cop	_	_
3	true	true	ADJ	JJ	Degree=Pos	0	root	_	_
4	about	about	ADP	IN	_	5	case	_	_
5	friction	friction	NOUN	NN	Number=Sing	3	obl	_	SpaceAfter=No
6	?	?	PUNCT	.	_	3	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is** | present |  |  |  |  |  | about friction; true *property* | tree rules |

<!-- .note -->
One row per clause the reader finds. «not said here»: a role filled from the clause above. «roles by»: a VerbNet class and frame when one fits the verb, else the reader's rules on the tree.

## The options {#options}

### Option 1 {#o1}

<!-- .ven lang=en -->
It is the same thing as gravity

```conllu
# sent_id = question:world:51-forces:t5:o1:1
# text = It is the same thing as gravity
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	5	nsubj	_	_
2	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	5	cop	_	_
3	the	the	DET	DT	Definite=Def|PronType=Art	5	det	_	_
4	same	same	ADJ	JJ	Degree=Pos	5	amod	_	_
5	thing	thing	NOUN	NN	Number=Sing	0	root	_	_
6	as	as	ADP	IN	_	7	case	_	_
7	gravity	gravity	NOUN	NN	Number=Sing	5	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is a** | present | It | the same thing |  |  |  | as gravity | tree rules |

### Option 2 {#o2}

<!-- .ven lang=en -->
It only exists between surfaces made of metal

```conllu
# sent_id = question:world:51-forces:t5:o2:1
# text = It only exists between surfaces made of metal
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	3	nsubj	_	_
2	only	only	ADV	RB	_	3	advmod	_	_
3	exists	exist	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
4	between	between	ADP	IN	_	5	case	_	_
5	surfaces	surface	NOUN	NNS	Number=Plur	3	obl	_	_
6	made	make	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	5	acl	_	_
7	of	of	ADP	IN	_	8	case	_	_
8	metal	metal	NOUN	NN	Number=Sing	6	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **exist** | present | It |  |  | surfaces |  |  | vn exist-47.1 «NP V PP.location»: agent=Theme between surface=Location |
| 2 | **make** | participle |  | surfaces *not said here* |  |  |  | of metal | vn build-26.1-1 «NP.asset V NP»: agent=Asset |

### Option 3 {#o3}

<!-- .ven lang=en -->
It always helps things move faster

```conllu
# sent_id = question:world:51-forces:t5:o3:1
# text = It always helps things move faster
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	3	nsubj	_	_
2	always	always	ADV	RB	PronType=Tot	3	advmod	_	_
3	helps	help	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
4	things	thing	NOUN	NNS	Number=Plur	3	obj	_	_
5	move	move	VERB	VB	VerbForm=Inf	3	xcomp	_	_
6	faster	fast	ADV	RBR	Degree=Cmp	5	advmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **help** | present | It | things |  |  |  | always *property* | vn help-72.1-1-1 «NP V NP S\_INF»: agent=Agent thing=Beneficiary clause=Theme |
| 2 | **move** | infinitive | things *not said here* |  |  |  |  | fast *property* | vn roll-51.3.1 «NP.theme V»: agent=Theme |

### Option 4 · ← Mova's choice · ✓ the right answer {#o4}

<!-- .ven lang=en -->
It works against movement and makes heat

```conllu
# sent_id = question:world:51-forces:t5:o4:1
# text = It works against movement and makes heat
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	2	nsubj	_	_
2	works	work	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	against	against	ADP	IN	_	4	case	_	_
4	movement	movement	NOUN	NN	Number=Sing	2	obl	_	_
5	and	and	CCONJ	CC	_	6	cc	_	_
6	makes	make	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	2	conj	_	_
7	heat	heat	NOUN	NN	Number=Sing	6	obj	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **work** | present | It |  |  |  |  | against movement | vn employment-95.3 «NP V»: agent=Agent |
| 2 | **make** | present |  | heat |  |  |  |  | vn build-26.1-1 «NP.asset V NP»: agent=Asset heat=Product |

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**Text:** the tests of Mova's primary school, written for Mova (`world/data/school/`), as the course runner gave them to the student. **Trees:** Mova's own parse — the `en` model on the CPU, when the site is built — not checked by a teacher; they may be wrong. **Frames:** Mova's frames reader (`prag`), each text read on its own. Elamur Cosmic License.

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