Swing and angular displacement

[bahtiyar]

hi, we are a few non-native English speaker physics teacher and we wrote some questions for an assessment book
but we can't be sure about this two similar question.
a) are they accurate for rules of English, are we use correct terms is there a necessary change?
b) are they accurate for rules of physics and are the answers accurate?
FIRST QUESTION

1. Homework Statement
A child on an playground swings through a total of 32°. If the displacement is equal on each side of the equilibrium position, what is the amplitude of this vibration?
a) 8° b)32° c)16° d)64°

Homework Equations

none

The Attempt at a Solution

one of my colleague says the answer should 8° I think it should be 16°
second

SECOND QUESTION

Homework Statement

the amplitude of a simple pendulum is 0.17 rad. what is the angular displacement of this pendulum for one complete cycle?
a)0.17 rad b)0.34 rad c) 0.51 rad d)0.68 rad

Homework Equations

none

The Attempt at a Solution

my colleague says the answer should 0.68 rad. I think it should be zero rad.

 

[CWatters]

The English is ok. Might be better to say "after one complete cycle". Your answers are correct 16 and 0.

The distance is 0.64 rads, the displacement is 0 rads.

 

[bahtiyar]

my colleague says there is no such a term as angular distance, so "angular displacement for one complete cycle" corresponds 4 times amplitude.
Do you have any reference, a link or textbook that use these terms?

 

[haruspex]

A child on an playground swings through a total of 32°.

This is ambiguous. It might be counting multiple traverses of the same arc. Depending on what is intended, could clarify by specifying "in a single direction" or "in one complete cycle"...

the displacement is equal

Which displacements? The maximum displacements from equilibrium or the initial and final displacements?

angular displacement for one complete cycle" corresponds 4 times amplitude.

Certainly not.
"Displacement" always means net change, regardless of path taken. If your colleague does not like "angular distance" then some other term must be found which makes the meaning clear.

 

[CWatters]

my colleague says there is no such a term as angular distance..

Normally we just use "angle" rather than angular distance. Angle can be greater than 2pi.

 

[haruspex]

Normally we just use "angle" rather than angular distance. Angle can be greater than 2pi.

Yes, but in regard to wording a question for students I feel that in itself would not be clear enough.

 

[bahtiyar]

thank you guys for making it clear what are your suggestions and answers