Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: The Scientist on 09/01/2011 03:04:19

Title: How do boomerangs work?
Post by: The Scientist on 09/01/2011 03:04:19

Why does a boomerang comes spinning back towards you when you throw it? What do you think? Thanks!

Title: How do boomerangs work?
Post by: Foolosophy on 09/01/2011 06:33:14

Why do boomerangs fly?

This is the 64,000 Euro question. First let me ask 10 fairly simple (but increasingly complicated!) related questions. If you can answer all of them, then you're well on the way to understanding how a boomerang works:

1. What is (near enough) the shape of the flight path of a boomerang?
A. out and back on a straight line;
B. circular;
C. around the four sides of a square.

2. If I swing a ball on string around my head it follows a circular path; in what direction does the force in the string act?
A. downwards;
B. always towards the centre of the circle;
C. there is no force in the string.

3. An aeroplane wing works because:
A. it is an anti-gravity device;
B. when it moves through the air at high speed it generates lift;
C. it flaps up and down.

4. A helicopter rotor has four blades each in the shape of:
A. a feather;
B. an airplane wing;
C. a circular tube.

5. A cross-shaped boomerang resembles a helicopter rotor because:
A. they both have four blades;
B. they both generate lift when they spin;
C. they work backwards as well as forwards.

6. The lift force of a spinning boomerang is directed mostly:
A. downwards;
B. towards the centre of its circular flight path;
C. there is no lift force.

7. As a spinning boomerang moves forward the uppermost blade moves:
A. at the same speed as the centre of the boomerang;
B. faster than the centre of the boomerang because it is spinning and moving forwards at the same time;
C. downwards.

8. The top of the boomerang generates more lift than the bottom because:
A. it is bigger;
B. it is moving faster;
C. it is heavier.

9. The difference in lift between the top and the bottom of the boomerang:
A. doesn't matter;
B. forms a couple which causes gyroscopic precession;
C. causes the boomerang to bend.

10. Lift on a boomerang causes circular motion and gyroscopic precession:
A. which is too complicated for me to understand;
B. which balance perfectly - truly a wonderful miracle of nature;
C. which the Aborigines could have told you 10,000 years ago.

Title: How do boomerangs work?
Post by: Geezer on 09/01/2011 07:01:05

We prefer that you don't answer a question with another question. We very much prefer that you don't answer a question with a whole bunch of questions that might be construed as an attempt to belittle the original poster.

Title: How do boomerangs work?
Post by: Foolosophy on 09/01/2011 09:27:07

Quote from: Geezer on 09/01/2011 07:01:05

We prefer that you don't answer a question with another question. We very much prefer that you don't answer a question with a whole bunch of questions that might be construed as an attempt to belittle the original poster.

Are you using the Royal "WE"?

The answer to the original question in the thread topic can be found by simply answering the 10 questions I posed.

I can delete the post if you find it offensive or NON-scientific

Title: How do boomerangs work?
Post by: Geezer on 09/01/2011 09:42:05

Quote from: Foolosophy on 09/01/2011 09:27:07

I can delete the post if you find it offensive or NON-scientific

Your call. But you might want to consider how you would react if someone posted a similar response to one of your questions, if you ever posted a question.

Title: How do boomerangs work?
Post by: Foolosophy on 09/01/2011 10:13:30

Quote from: Geezer on 09/01/2011 09:42:05

Quote from: Foolosophy on 09/01/2011 09:27:07

I can delete the post if you find it offensive or NON-scientific

Your call. But you might want to consider how you would react if someone posted a similar response to one of your questions, if you ever posted a question.

You might want to consider the same thing.

I didnt realise that you were "THE SCIENTIST"

THE SCIENTIST didnt seem to raise any objections

If THE SCIENTIST wants me to delete that post he can ask me and I will have no problem in doing so

HIS CALL

Title: How do boomerangs work?
Post by: The Scientist on 09/01/2011 10:20:18

Quote from: Foolosophy on 09/01/2011 06:33:14

Why do boomerangs fly?

This is the 64,000 Euro question. First let me ask 10 fairly simple (but increasingly complicated!) related questions. If you can answer all of them, then you're well on the way to understanding how a boomerang works:

1. What is (near enough) the shape of the flight path of a boomerang?
A. out and back on a straight line;
B. circular;
C. around the four sides of a square.

2. If I swing a ball on string around my head it follows a circular path; in what direction does the force in the string act?
A. downwards;
B. always towards the centre of the circle;
C. there is no force in the string.

3. An aeroplane wing works because:
A. it is an anti-gravity device;
B. when it moves through the air at high speed it generates lift;
C. it flaps up and down.

4. A helicopter rotor has four blades each in the shape of:
A. a feather;
B. an airplane wing;
C. a circular tube.

5. A cross-shaped boomerang resembles a helicopter rotor because:
A. they both have four blades;
B. they both generate lift when they spin;
C. they work backwards as well as forwards.

6. The lift force of a spinning boomerang is directed mostly:
A. downwards;
B. towards the centre of its circular flight path;
C. there is no lift force.

7. As a spinning boomerang moves forward the uppermost blade moves:
A. at the same speed as the centre of the boomerang;
B. faster than the centre of the boomerang because it is spinning and moving forwards at the same time;
C. downwards.

8. The top of the boomerang generates more lift than the bottom because:
A. it is bigger;
B. it is moving faster;
C. it is heavier.

9. The difference in lift between the top and the bottom of the boomerang:
A. doesn't matter;
B. forms a couple which causes gyroscopic precession;
C. causes the boomerang to bend.

10. Lift on a boomerang causes circular motion and gyroscopic precession:
A. which is too complicated for me to understand;
B. which balance perfectly - truly a wonderful miracle of nature;
C. which the Aborigines could have told you 10,000 years ago.

Thanks for the questions. But may I ask for the answers?

Title: How do boomerangs work?
Post by: SeanB on 09/01/2011 10:31:48

In all cases "B" would apply, except for number 10,. where both "B" and "C" are relevant.

Title: How do boomerangs work?
Post by: syhprum on 09/01/2011 11:05:12

There is a great tradition of answering a question by discussing with the questioner what he already knows about the subject and getting him to think more deeply about it.
It must be be done in a constructive manor and care taken not to get in to a useless circle.

Title: How do boomerangs work?
Post by: Foolosophy on 09/01/2011 11:17:47

Quote from: syhprum on 09/01/2011 11:05:12

There is a great tradition of answering a question by discussing with the questioner what he already knows about the subject and getting him to think more deeply about it.
It must be be done in a constructive manor and care taken not to get in to a useless circle.

all circles are useful