the enigmatic zipper

[RichD]

I've noticed that nobody knows how a zipper works.

You've got two tracks of teeth which mesh, that's
obvious. But no one can explain the fastener. How
does it zip and unzip?

Try a different tack - what causes it to malfunction?
Which they always do, eventually In one case, the
process doesn't start, the tracks refuse to mesh.
In another case, the tracks mesh, it zips halfway...
then they unmesh. What gives?


--
Rich

[Grunty]

Post by RichD
I've noticed that nobody knows how a zipper works.
You've got two tracks of teeth which mesh, that's
obvious. But no one can explain the fastener. How
does it zip and unzip?
Try a different tack - what causes it to malfunction?
Which they always do, eventually In one case, the
process doesn't start, the tracks refuse to mesh.
In another case, the tracks mesh, it zips halfway...
then they unmesh. What gives?

Let me guess... Yesterday you were wandering in a mall looking for some nice Xmas gift for the granddaughter. Suddenly your zipper got derailed without you even noticing. You spent the whole evening showing your Mickey Mice at every shop you'd enter.

[da pickle]

Post by Grunty

Post by RichD
I've noticed that nobody knows how a zipper works.
You've got two tracks of teeth which mesh, that's
obvious. But no one can explain the fastener. How
does it zip and unzip?
Try a different tack - what causes it to malfunction?
Which they always do, eventually In one case, the
process doesn't start, the tracks refuse to mesh.
In another case, the tracks mesh, it zips halfway...
then they unmesh. What gives?

Let me guess... Yesterday you were wandering in a mall looking for some nice Xmas gift for the granddaughter. Suddenly your zipper got derailed without you even noticing. You spent the whole evening showing your Mickey Mice at every shop you'd enter.

Google might answer his question.

About 66,500,000 results (0.42 seconds)

[RichD]

Post by Grunty

Post by RichD
I've noticed that nobody knows how a zipper works.
You've got two tracks of teeth which mesh, that's
obvious. But no one can explain the fastener. How
does it zip and unzip?
Try a different tack - what causes it to malfunction?
Which they always do, eventually In one case, the
process doesn't start, the tracks refuse to mesh.
In another case, the tracks mesh, it zips halfway...
then they unmesh. What gives?

Let me guess... Yesterday you were wandering in a mall looking for some nice Xmas gift
for the granddaughter. Suddenly your zipper got derailed without you even noticing.
You spent the whole evening showing your Mickey Mice at every shop you'd enter.

Try it yourself. Ask your friends and lawyer about the zipper. No can explain!

Another one I use: You're in a passenger aircraft with a high
ceiling (like an air force transport), traveling 500 mph. The overhead
bin opens, a bag falls.
i) It falls toward the seat in front, as it picks up a kick from
the plane's momentum.
ii) It falls straight to the seat below.
iii) It falls straight down to earth, hence landing in the seat behind.

3 out of 4 get it wrong, in my experience -

--
Rich

[da pickle]

Post by RichD

Post by Grunty

Post by RichD
I've noticed that nobody knows how a zipper works.
You've got two tracks of teeth which mesh, that's
obvious. But no one can explain the fastener. How
does it zip and unzip?
Try a different tack - what causes it to malfunction?
Which they always do, eventually In one case, the
process doesn't start, the tracks refuse to mesh.
In another case, the tracks mesh, it zips halfway...
then they unmesh. What gives?

Let me guess... Yesterday you were wandering in a mall looking for some nice Xmas gift
for the granddaughter. Suddenly your zipper got derailed without you even noticing.
You spent the whole evening showing your Mickey Mice at every shop you'd enter.

Try it yourself. Ask your friends and lawyer about the zipper. No can explain!
Another one I use: You're in a passenger aircraft with a high
ceiling (like an air force transport), traveling 500 mph. The overhead
bin opens, a bag falls.
i) It falls toward the seat in front, as it picks up a kick from
the plane's momentum.
ii) It falls straight to the seat below.
iii) It falls straight down to earth, hence landing in the seat behind.
3 out of 4 get it wrong, in my experience -
--
Rich

ii

[VegasJerry]

Post by Grunty

Post by RichD
I've noticed that nobody knows how a zipper works.
You've got two tracks of teeth which mesh, that's
obvious. But no one can explain the fastener. How
does it zip and unzip?
Try a different tack - what causes it to malfunction?
Which they always do, eventually In one case, the
process doesn't start, the tracks refuse to mesh.
In another case, the tracks mesh, it zips halfway...
then they unmesh. What gives?

Let me guess... Yesterday you were wandering in a mall looking for some nice Xmas gift
for the granddaughter. Suddenly your zipper got derailed without you even noticing.
You spent the whole evening showing your Mickey Mice at every shop you'd enter.

Try it yourself. Ask your friends and lawyer about the zipper. No can explain!
Another one I use: You're in a passenger aircraft with a high
ceiling (like an air force transport), traveling 500 mph. The overhead
bin opens, a bag falls.
i) It falls toward the seat in front, as it picks up a kick from
the plane's momentum.
ii) It falls straight to the seat below.
iii) It falls straight down to earth, hence landing in the seat behind.
3 out of 4 get it wrong, in my experience -
--
Rich

.

Any particular reason for using, i, ii, iii rather than 1,2,3 or A, B, C?

[da pickle]

Post by VegasJerry

Post by Grunty

Post by RichD
I've noticed that nobody knows how a zipper works.
You've got two tracks of teeth which mesh, that's
obvious. But no one can explain the fastener. How
does it zip and unzip?
Try a different tack - what causes it to malfunction?
Which they always do, eventually In one case, the
process doesn't start, the tracks refuse to mesh.
In another case, the tracks mesh, it zips halfway...
then they unmesh. What gives?

Let me guess... Yesterday you were wandering in a mall looking for some nice Xmas gift
for the granddaughter. Suddenly your zipper got derailed without you even noticing.
You spent the whole evening showing your Mickey Mice at every shop you'd enter.

Try it yourself. Ask your friends and lawyer about the zipper. No can explain!
Another one I use: You're in a passenger aircraft with a high
ceiling (like an air force transport), traveling 500 mph. The overhead
bin opens, a bag falls.
i) It falls toward the seat in front, as it picks up a kick from
the plane's momentum.
ii) It falls straight to the seat below.
iii) It falls straight down to earth, hence landing in the seat behind.
3 out of 4 get it wrong, in my experience -
--
Rich

.
Any particular reason for using, i, ii, iii rather than 1,2,3 or A, B, C?

Ever dropped something in your car? [That iii is weirdly stated.]

[RichD]

Post by da pickle

Post by RichD
You're in a passenger aircraft with a high
ceiling (like an air force transport), traveling 500 mph. The overhead
bin opens, a bag falls.
i) It falls toward the seat in front, as it picks up a kick from
the plane's momentum.
ii) It falls straight to the seat below.
iii) It falls straight down to earth, hence landing in the seat behind.
3 out of 4 get it wrong, in my experience -

Ever dropped something in your car?

You sit in a bus with high roof, holding a helium balloon, which floats
high. The bus makes a sharp, high speed left turn. How does the
balloon respond?

--
Rich

[VegasJerry]

Post by RichD

Post by da pickle

Post by RichD
You're in a passenger aircraft with a high
ceiling (like an air force transport), traveling 500 mph. The overhead
bin opens, a bag falls.
i) It falls toward the seat in front, as it picks up a kick from
the plane's momentum.
ii) It falls straight to the seat below.
iii) It falls straight down to earth, hence landing in the seat behind.
3 out of 4 get it wrong, in my experience -

Ever dropped something in your car?

.

Post by RichD
You sit in a bus with high roof, holding a helium balloon, which floats
high. The bus makes a sharp, high speed left turn. How does the
balloon respond?

.
It moves left..

Post by RichD
--
Rich

[RichD]

Post by VegasJerry

Post by RichD
You sit in a bus with high roof, holding a helium balloon, which floats
high. The bus makes a sharp, high speed left turn. How does the
balloon respond?

It moves left.

Good guess. Now, as the teacher said, show your work -

--
Rich

[VegasJerry]

Post by VegasJerry

Post by RichD
You sit in a bus with high roof, holding a helium balloon, which floats
high. The bus makes a sharp, high speed left turn. How does the
balloon respond?

It moves left.

Good guess. Now, as the teacher said, show your work -
--
Rich

.

Wasn't a guess. Air is heavier than helium...

[Tim Norfolk]

Post by Grunty

Post by RichD
I've noticed that nobody knows how a zipper works.
You've got two tracks of teeth which mesh, that's
obvious. But no one can explain the fastener. How
does it zip and unzip?
Try a different tack - what causes it to malfunction?
Which they always do, eventually In one case, the
process doesn't start, the tracks refuse to mesh.
In another case, the tracks mesh, it zips halfway...
then they unmesh. What gives?

Let me guess... Yesterday you were wandering in a mall looking for some nice Xmas gift
for the granddaughter. Suddenly your zipper got derailed without you even noticing.
You spent the whole evening showing your Mickey Mice at every shop you'd enter.

Try it yourself. Ask your friends and lawyer about the zipper. No can explain!
Another one I use: You're in a passenger aircraft with a high
ceiling (like an air force transport), traveling 500 mph. The overhead
bin opens, a bag falls.
i) It falls toward the seat in front, as it picks up a kick from
the plane's momentum.
ii) It falls straight to the seat below.
iii) It falls straight down to earth, hence landing in the seat behind.
3 out of 4 get it wrong, in my experience -
--
Rich

ii) is the closest, but the bag likely loses a tiny bit of momentum as it falls.

[da pickle]

Post by Tim Norfolk

Post by Grunty

Post by RichD
I've noticed that nobody knows how a zipper works.
You've got two tracks of teeth which mesh, that's
obvious. But no one can explain the fastener. How
does it zip and unzip?
Try a different tack - what causes it to malfunction?
Which they always do, eventually In one case, the
process doesn't start, the tracks refuse to mesh.
In another case, the tracks mesh, it zips halfway...
then they unmesh. What gives?

Let me guess... Yesterday you were wandering in a mall looking for some nice Xmas gift
for the granddaughter. Suddenly your zipper got derailed without you even noticing.
You spent the whole evening showing your Mickey Mice at every shop you'd enter.

Try it yourself. Ask your friends and lawyer about the zipper. No can explain!
Another one I use: You're in a passenger aircraft with a high
ceiling (like an air force transport), traveling 500 mph. The overhead
bin opens, a bag falls.
i) It falls toward the seat in front, as it picks up a kick from
the plane's momentum.
ii) It falls straight to the seat below.
iii) It falls straight down to earth, hence landing in the seat behind.
3 out of 4 get it wrong, in my experience -
--
Rich

ii) is the closest, but the bag likely loses a tiny bit of momentum as it falls.

I agree ... emphasis on the word "tiny" ...

[We all must remember too that the plane is not flying in a "straight"
line.]

[Grunty]

Post by Tim Norfolk

Post by Grunty

Post by RichD
I've noticed that nobody knows how a zipper works.
You've got two tracks of teeth which mesh, that's
obvious. But no one can explain the fastener. How
does it zip and unzip?
Try a different tack - what causes it to malfunction?
Which they always do, eventually In one case, the
process doesn't start, the tracks refuse to mesh.
In another case, the tracks mesh, it zips halfway...
then they unmesh. What gives?

Let me guess... Yesterday you were wandering in a mall looking for some nice Xmas gift
for the granddaughter. Suddenly your zipper got derailed without you even noticing.
You spent the whole evening showing your Mickey Mice at every shop you'd enter.

Try it yourself. Ask your friends and lawyer about the zipper. No can explain!
Another one I use: You're in a passenger aircraft with a high
ceiling (like an air force transport), traveling 500 mph. The overhead
bin opens, a bag falls.
i) It falls toward the seat in front, as it picks up a kick from
the plane's momentum.
ii) It falls straight to the seat below.
iii) It falls straight down to earth, hence landing in the seat behind.
3 out of 4 get it wrong, in my experience -
--
Rich

ii) is the closest, but the bag likely loses a tiny bit of momentum as it falls.

I might be wrong cuz I'm going by memory.

The bag does not lose any momentum, as it forms, as do every thing inside the cabin, an 'inertial system' with the whole plane.
The bag would >boink< on the head of the passenger seated right under the bin, in a vertical trajectory. So my choice is -exactly- ii.

[VegasJerry]

Post by Grunty

Post by Tim Norfolk

Post by Grunty

Post by RichD
I've noticed that nobody knows how a zipper works.
You've got two tracks of teeth which mesh, that's
obvious. But no one can explain the fastener. How
does it zip and unzip?
Try a different tack - what causes it to malfunction?
Which they always do, eventually In one case, the
process doesn't start, the tracks refuse to mesh.
In another case, the tracks mesh, it zips halfway...
then they unmesh. What gives?

Let me guess... Yesterday you were wandering in a mall looking for some nice Xmas gift
for the granddaughter. Suddenly your zipper got derailed without you even noticing.
You spent the whole evening showing your Mickey Mice at every shop you'd enter.

Try it yourself. Ask your friends and lawyer about the zipper. No can explain!
Another one I use: You're in a passenger aircraft with a high
ceiling (like an air force transport), traveling 500 mph. The overhead
bin opens, a bag falls.
i) It falls toward the seat in front, as it picks up a kick from
the plane's momentum.
ii) It falls straight to the seat below.
iii) It falls straight down to earth, hence landing in the seat behind.
3 out of 4 get it wrong, in my experience -
--
Rich

ii) is the closest, but the bag likely loses a tiny bit of momentum as it falls.

.

Post by Grunty
I might be wrong cuz I'm going by memory.
The bag does not lose any momentum, as it forms, as do every thing inside the cabin, an 'inertial system' with the whole plane.
The bag would >boink< on the head of the passenger seated right under the bin, in a vertical trajectory. So my choice is -exactly- ii.

.

Me 2

[Tim Norfolk]

Post by Grunty

Post by Tim Norfolk

Post by Grunty

Post by RichD
I've noticed that nobody knows how a zipper works.
You've got two tracks of teeth which mesh, that's
obvious. But no one can explain the fastener. How
does it zip and unzip?
Try a different tack - what causes it to malfunction?
Which they always do, eventually In one case, the
process doesn't start, the tracks refuse to mesh.
In another case, the tracks mesh, it zips halfway...
then they unmesh. What gives?

Let me guess... Yesterday you were wandering in a mall looking for some nice Xmas gift
for the granddaughter. Suddenly your zipper got derailed without you even noticing.
You spent the whole evening showing your Mickey Mice at every shop you'd enter.

Try it yourself. Ask your friends and lawyer about the zipper. No can explain!
Another one I use: You're in a passenger aircraft with a high
ceiling (like an air force transport), traveling 500 mph. The overhead
bin opens, a bag falls.
i) It falls toward the seat in front, as it picks up a kick from
the plane's momentum.
ii) It falls straight to the seat below.
iii) It falls straight down to earth, hence landing in the seat behind.
3 out of 4 get it wrong, in my experience -
--
Rich

ii) is the closest, but the bag likely loses a tiny bit of momentum as it falls.

.

Post by Grunty
I might be wrong cuz I'm going by memory.
The bag does not lose any momentum, as it forms, as do every thing inside the cabin, an 'inertial system' with the whole plane.
The bag would >boink< on the head of the passenger seated right under the bin, in a vertical trajectory. So my choice is -exactly- ii.

.
Me 2

The bag is in freefall for a short time, without the impetus provided by the contact with the plane. There will be a tiny loss due to the air in the plane, I suspect.

[RichD]

Post by Grunty

Post by RichD
You're in a passenger aircraft with a high
ceiling (like an air force transport), traveling 500 mph. The overhead
bin opens, a bag falls.
i) It falls toward the seat in front, as it picks up a kick from
the plane's momentum.
ii) It falls straight to the seat below.
iii) It falls straight down to earth, hence landing in the seat behind.
3 out of 4 get it wrong, in my experience -

I might be wrong cuz I'm going by memory.
The bag does not lose any momentum, as it forms, as do every thing inside the cabin,
an 'inertial system' with the whole plane.
The bag would >boink< on the head of the passenger seated right under the bin, in a
vertical trajectory. So my choice is -exactly- ii.

Good.

Now the Master level: Paul Passenger is in aisle 12 of a jet, at 10000 feet,
500 mph. He holds two super rubber balls, which always bounce up to
the level where they were released; no energy loss.

He holds one ball high, then drops it. Where does it return, relative to his hand?

He opens a window, releases the other ball. The earth below is a giant
sheet of flat marble. Ignore air resistance. (in these ideal physics problems,
there's never friction or air resistance) It falls, and bounces back to the
height released. When it hits that peak, where is it, relative to Paul?

--
Rich