Find all School-related info fast with the new School-Specific MBA Forum

It is currently 24 Oct 2014, 05:56

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Doppler Effect

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Manager
Manager
avatar
Joined: 21 Mar 2008
Posts: 244
Followers: 2

Kudos [?]: 17 [0], given: 0

Doppler Effect [#permalink] New post 05 Jun 2008, 13:12
The “Doppler effect” refers to the perceived change in pitch that occurs when the source of a sound is in motion relative to the observer. For example, the siren on a passing police car will sound higher than its true pitch as the car approaches, sound the same as its true pitch as the car passes, and sound lower than its true pitch as the car travels away from the observer.

If two trains pass each other going opposite directions on parallel east-west tracks, which of the following observations provides another illustration of the effect described above?

A. If the eastbound train blows its horn as they pass, passengers on the westbound train will hear a sound that decreases in pitch.

B. If the eastbound train blows its horn as they pass, passengers on the westbound train will hear a sound that increases in pitch.

C. If the eastbound train blows its horn as they pass, passengers on the eastbound train will hear a sound that decreases in pitch.

D. If the eastbound train blows its horn as they pass, passengers on the eastbound train will hear a sound that increases in pitch.

E. If the eastbound train blows its horn as they pass, passengers on the eastbound train will hear a sound that is steady in pitch.

Source MGMAT. Will post OA after some discussion.
Manhattan GMAT Discount CodesKaplan GMAT Prep Discount CodesVeritas Prep GMAT Discount Codes
CEO
CEO
User avatar
Joined: 29 Mar 2007
Posts: 2593
Followers: 16

Kudos [?]: 197 [0], given: 0

Re: Doppler Effect [#permalink] New post 05 Jun 2008, 13:27
Sunny143 wrote:
The “Doppler effect” refers to the perceived change in pitch that occurs when the source of a sound is in motion relative to the observer. For example, the siren on a passing police car will sound higher than its true pitch as the car approaches, sound the same as its true pitch as the car passes, and sound lower than its true pitch as the car travels away from the observer.

If two trains pass each other going opposite directions on parallel east-west tracks, which of the following observations provides another illustration of the effect described above?

A. If the eastbound train blows its horn as they pass, passengers on the westbound train will hear a sound that decreases in pitch.

B. If the eastbound train blows its horn as they pass, passengers on the westbound train will hear a sound that increases in pitch.

C. If the eastbound train blows its horn as they pass, passengers on the eastbound train will hear a sound that decreases in pitch.

D. If the eastbound train blows its horn as they pass, passengers on the eastbound train will hear a sound that increases in pitch.

E. If the eastbound train blows its horn as they pass, passengers on the eastbound train will hear a sound that is steady in pitch.

Source MGMAT. Will post OA after some discussion.



Seems to be A.

While E is true, it doesnt really follow the force of the argument. Arguably I think E could be an answer though.
SVP
SVP
avatar
Joined: 28 Dec 2005
Posts: 1593
Followers: 2

Kudos [?]: 75 [0], given: 2

Re: Doppler Effect [#permalink] New post 05 Jun 2008, 15:05
A for me as well
Manager
Manager
avatar
Joined: 21 Mar 2008
Posts: 244
Followers: 2

Kudos [?]: 17 [0], given: 0

Re: Doppler Effect [#permalink] New post 05 Jun 2008, 16:19
Thanks for posting responses, but dont you guys think that according to the answer choice A, if the horn is blown when the 2 trains PASS, then some part of the westbound train will already have passed( the passengers in that part are going away from the horn, so they hear a decreasing pitch), but the rest of the passengers who are in the part of the train that is yet to pass , they are coming towards the horn, hence they should hear a increasing pitch.


Thoughts?

OA a little later
Manager
Manager
avatar
Joined: 01 May 2008
Posts: 114
Location: São Paulo
Followers: 1

Kudos [?]: 4 [0], given: 0

Re: Doppler Effect [#permalink] New post 05 Jun 2008, 17:19
I think the best answer for the passenger in the part of the train that is yet to pass would be that they would hear an increasing pitch, and then an decreasing pitch, as the other traisn goes away. Once there's not that answer, the best answer is A for me too.
Manager
Manager
avatar
Joined: 21 Mar 2008
Posts: 244
Followers: 2

Kudos [?]: 17 [0], given: 0

Re: Doppler Effect [#permalink] New post 06 Jun 2008, 06:40
OA is A.

But again, I dont fully agree with the MGMAT OA. As someone said, they are a bit rough on the edges with their CR. Only E makes some logical sense here among the choices...
Manager
Manager
avatar
Joined: 01 May 2008
Posts: 114
Location: São Paulo
Followers: 1

Kudos [?]: 4 [0], given: 0

Re: Doppler Effect [#permalink] New post 06 Jun 2008, 10:26
I think the key issue here is that the question is asking "which of the following observations provides another illustration of the effect described above".
Answer E does make more logical sense, but doesn´t illustrate the doppler efect
Director
Director
User avatar
Joined: 01 Jan 2008
Posts: 513
Followers: 3

Kudos [?]: 45 [0], given: 0

Reviews Badge
Re: Doppler Effect [#permalink] New post 19 Jun 2008, 08:23
Given example
------> Car A
-------> Car B

Car A blows siren... Car B hears increasing sound as A is approaching. ( Same direction )

Given Question

------> Train A
<------- Train B

Train A and B in oppopsite directions, therefore when A is approaching, B is in opposite directions hence due to doppler effect , it will hear sound decreasing in pitch.

Only A explains the same.
Manager
Manager
avatar
Joined: 21 Mar 2008
Posts: 244
Followers: 2

Kudos [?]: 17 [0], given: 0

Re: Doppler Effect [#permalink] New post 19 Jun 2008, 09:12
Think of one person on the train...it is said that the horn is blown when the 2 trains pass...So think of a person who is at the end of the westbound. So when the eastbound train sounds the horn when they pass..the person in the last compartment of the westbound train will hear a increasing pitch first and then a decreasing pitch as the 2 trains completely pass...

The OA A comes closest in a very bad bunch. None of them are scientifically sound...but again one might argue that we are here efor CR questions...
Re: Doppler Effect   [#permalink] 19 Jun 2008, 09:12
    Similar topics Author Replies Last post
Similar
Topics:
The “Doppler effect” refers to the universally perceived cha Rock750 0 13 Jan 2014, 01:58
3 Experts publish their posts in the topic The Doppler effect refers to the perceived change in pitch skim 25 08 Dec 2009, 01:41
The Doppler effect refers to the perceived change in pitch dancinggeometry 2 13 Sep 2008, 01:57
The Doppler effect refers to the perceived change in pitch FN 7 17 Jun 2008, 10:40
Doppler - alimad alimad 9 20 Sep 2006, 06:09
Display posts from previous: Sort by

Doppler Effect

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.