---
title: Identify the principal reason for which the brakes of a bicycle are… — Friction: the grip that stops and helps · tree and pragmatics
description: Identify the principal reason for which the brakes of a bicycle are rendered less effective in wet conditions. Exam question 2 of lesson 6 «Friction: the grip that stops and helps» of the physics course of Mova's primary school, with the dependency tree and pragmatics of the question and of each opt
---

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# Exam question 2 · Friction: the grip that stops and helps

<!-- .ven lang=en -->
Identify the principal reason for which the brakes of a bicycle are rendered less effective in wet conditions.

<!-- .vintro -->
**Mova's choice:** option 1 · **The right answer:** option 3 · wrong ✗ · **Who acts:** you · **What happens:** identify, render · **To what, where:** principal reason, brakes, wet conditions

<!-- .vabout -->
This is exam question 2 of lesson 6 «Friction: the grip that stops and helps» of the physics course of Mova's primary school, asked in stiff, formal language. 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/physics/6-friction-the-grip/#e2).

## The question {#question}

```conllu
# sent_id = question:physics:6-friction-the-grip:e2:1
# text = Identify the principal reason for which the brakes of a bicycle are rendered less effective in wet conditions.
1	Identify	identify	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
3	principal	principal	ADJ	JJ	Degree=Pos	4	amod	_	_
4	reason	reason	NOUN	NN	Number=Sing	1	obj	_	_
5	for	for	ADP	IN	_	6	case	_	_
6	which	which	PRON	WDT	PronType=Rel	13	obl	_	_
7	the	the	DET	DT	Definite=Def|PronType=Art	8	det	_	_
8	brakes	brake	NOUN	NNS	Number=Plur	13	nsubj:pass	_	_
9	of	of	ADP	IN	_	11	case	_	_
10	a	a	DET	DT	Definite=Ind|PronType=Art	11	det	_	_
11	bicycle	bicycle	NOUN	NN	Number=Sing	8	nmod	_	_
12	are	be	AUX	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	13	aux:pass	_	_
13	rendered	render	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	4	acl:relcl	_	_
14	less	less	ADV	RBR	Degree=Cmp	15	advmod	_	_
15	effective	effective	ADJ	JJ	Degree=Pos	13	xcomp	_	_
16	in	in	ADP	IN	_	18	case	_	_
17	wet	wet	ADJ	JJ	Degree=Pos	18	amod	_	_
18	conditions	condition	NOUN	NNS	Number=Plur	13	obl	_	SpaceAfter=No
19	.	.	PUNCT	.	_	1	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **identify** | imperative | you *not said here* | the principal reason |  |  |  |  | vn characterize-29.2-1-1 «NP V NP S\_ING»: agent=Agent reason=Theme |
| 2 | **render** | present · passive |  | the brakes of a bicycle |  | wet conditions |  | for the principal reason; effective *property* | vn give-13.1 «NP V NP»: subject=Theme |

<!-- .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 · ← Mova's choice {#o1}

<!-- .ven lang=en -->
Water causes the tyres to become inflated

```conllu
# sent_id = question:physics:6-friction-the-grip:e2:o1:1
# text = Water causes the tyres to become inflated
1	Water	water	NOUN	NN	Number=Sing	2	nsubj	_	_
2	causes	cause	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
4	tyres	tyre	NOUN	NNS	Number=Plur	2	obj	_	_
5	to	to	PART	TO	_	6	mark	_	_
6	become	become	VERB	VB	VerbForm=Inf	2	advcl	_	_
7	inflated	inflate	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	6	xcomp	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **cause** | present | Water | the tyres |  |  |  |  | vn engender-27.1-1 «NP V NP»: agent=Precondition tyre=Patient |
| 2 | **become** | to-infinitive | Water *not said here* |  |  |  |  |  | tree rules |
| 3 | **inflate** | participle | Water *not said here* |  |  |  |  |  | vn bend-45.2 «NP.patient V»: agent=Patient |

### Option 2 {#o2}

<!-- .ven lang=en -->
Water increases the mass of the wheel

```conllu
# sent_id = question:physics:6-friction-the-grip:e2:o2:1
# text = Water increases the mass of the wheel
1	Water	water	NOUN	NN	Number=Sing	2	nsubj	_	_
2	increases	increase	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
4	mass	mass	NOUN	NN	Number=Sing	2	obj	_	_
5	of	of	ADP	IN	_	7	case	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
7	wheel	wheel	NOUN	NN	Number=Sing	4	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **increase** | present | Water | the mass of the wheel |  |  |  |  | vn caused\_calibratable\_cos-45.6.2-1 «NP V NP.patient»: agent=Causer mass=Patient |

### Option 3 · ✓ the right answer {#o3}

<!-- .ven lang=en -->
Water between pad and rim diminishes their grip

```conllu
# sent_id = question:physics:6-friction-the-grip:e2:o3:1
# text = Water between pad and rim diminishes their grip
1	Water	water	NOUN	NN	Number=Sing	6	nsubj	_	_
2	between	between	ADP	IN	_	3	case	_	_
3	pad	pad	NOUN	NN	Number=Sing	1	nmod	_	_
4	and	and	CCONJ	CC	_	5	cc	_	_
5	rim	rim	NOUN	NN	Number=Sing	3	conj	_	_
6	diminishes	diminish	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
7	their	their	PRON	PRP$	Case=Gen|Number=Plur|Person=3|Poss=Yes|PronType=Prs	8	nmod:poss	_	_
8	grip	grip	NOUN	NN	Number=Sing	6	obj	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **diminish** | present | Water between pad and rim | pad's grip |  |  |  |  | vn caused\_calibratable\_cos-45.6.2-1 «NP V NP.patient»: agent=Causer grip=Patient |
| 2 | **grip** |  | pad |  |  |  |  |  | nom grip «act transitive»: poss=agent |

### Option 4 {#o4}

<!-- .ven lang=en -->
Water lowers the temperature of the rider's hands

```conllu
# sent_id = question:physics:6-friction-the-grip:e2:o4:1
# text = Water lowers the temperature of the rider's hands
1	Water	water	NOUN	NN	Number=Sing	2	nsubj	_	_
2	lowers	lower	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
4	temperature	temperature	NOUN	NN	Number=Sing	2	obj	_	_
5	of	of	ADP	IN	_	9	case	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
7	rider	rider	NOUN	NN	Number=Sing	9	nmod:poss	_	SpaceAfter=No
8	's	's	PART	POS	_	7	case	_	_
9	hands	hand	NOUN	NNS	Number=Plur	4	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **lower** | present | Water | the temperature of the rider's hands |  |  |  |  | vn put\_direction-9.4 «NP V NP»: agent=Agent temperature=Theme |

<!-- div src -->

**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.

<!-- /div -->

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- ← previous: [Friction: the grip that stops and helps, exam 1](https://md.mova.elamur.ai/free/en/corpora/questions/physics/6-friction-the-grip/e1/)
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