Re: OT - "as if" physics question

[Yves Caudano]

I know I’m late in the discussion but I just saw the thread now and, as a 
physicist, I thought I could provide some insights into this question (but no 
answer).

One way of seing the problem is to consider only the vertical movement 
(equivalent to standing in an elevator going up in small steps with stops 
between them). The stress this puts on the body would be related to the maximum 
vertical acceleration each time you step up. I did a quick estimate and perhaps 
that could correspond to a ~15% increase of stress relative to standing still 
(equivalent to adding 15% mass to the bag and to the person).

Another component of the problem is the actual biomechanics of climbing the 
stairs while maintaining balance. This is the tricky part because it involves 
"lever problems”. I expect this is the biggest source of stress, especially if 
your body position is not optimal, because lever problems involve multiplying 
factors. Therefore, the forces exerted locally by muscles and joints to prevent 
rotational and torsional imbalances can be much larger than the force required 
to simply carry the bag (equivalent to multiplying the mass of the bag by a 
possibly large factor). We normally dont’ hold heavy loads at arm’s length for 
this reason and we shouldn’t lift loads by bending forward for this reason as 
well (when lifting by bending forward, I believe the multiplying factor can 
reach ~20 in the lower back).

I guess my message is: in terms of body stress there’s more to stair climbing 
than vertical lift.

Yves

On 24 Jun 2017, at 18:33, ann sanfedele  wrote:

> What is the difference in virtual weight of a pack (say, ten lbs) being 
> carried bys omeone walking on level ground and the same person carrying
> the same pack up a flight of stairs?
> 
> I'm sure I'm not using the corrrect terms here, I"m sure but I'm looking for 
> the as if  related to the stress it puts on my body.
> 
> Is it like I'm carrying 5 more lbs?  20 more lbs?  etc
> 
> answer ON list so ten people don't have to respond :-)
> 
> thanks, guys
> 
> ann
> 
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Re: OT - "as if" physics question

[ann sanfedele]

in my case, it would be more like restless cat syndrome

a

On 6/25/2017 1:05 PM, Alan C wrote:

Restless leg syndrome?

Alan C

-Original Message- From: ann sanfedele
Sent: Sunday, June 25, 2017 6:48 PM
To: Steve Cottrell ; Pentax-Discuss Mail List
Subject: Re: OT - "as if" physics question

thought you'd like to know that :-)

ann

On 6/25/2017 12:40 PM, Steve Cottrell wrote:

On 25/6/17, ann sanfedele, discombobulated, unleashed:


I was happy to learn that even asleep we burn calories

Here here!







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Re: OT - "as if" physics question

[Alan C]

Restless leg syndrome?

Alan C

-Original Message- 
From: ann sanfedele

Sent: Sunday, June 25, 2017 6:48 PM
To: Steve Cottrell ; Pentax-Discuss Mail List
Subject: Re: OT - "as if" physics question

thought you'd like to know that :-)

ann

On 6/25/2017 12:40 PM, Steve Cottrell wrote:

On 25/6/17, ann sanfedele, discombobulated, unleashed:


I was happy to learn that even asleep we burn calories

Here here!




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Re: OT - "as if" physics question

[ann sanfedele]

thought you'd like to know that :-)

ann

On 6/25/2017 12:40 PM, Steve Cottrell wrote:

On 25/6/17, ann sanfedele, discombobulated, unleashed:


I was happy to learn that even asleep we burn calories

Here here!




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Re: OT - "as if" physics question

[Bob W-PDML]

> On 25 Jun 2017, at 17:16, Steve Cottrell  wrote:
> 
> On 25/6/17, Jostein, discombobulated, unleashed:
> 
>> So if you just stand still there's no energy spent?
> 
> Steve's Law:
> 
> A body at rest tends to fall asleep.
> 
> True.
> 

I think we are now straying into the realm of metabolics.



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Re: OT - "as if" physics question

[Steve Cottrell]

On 25/6/17, Jostein, discombobulated, unleashed:

>So if you just stand still there's no energy spent?

Steve's Law:

A body at rest tends to fall asleep.

True.

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Re: OT - "as if" physics question

[P. J. Alling]

That is a complicating factor, you spend energy, whether you want to or 
not.  If you stand still there's no additional energy spent, and my 
calculations may be off by an order of magnitude.  I didn't bother to 
check my work.



On 6/25/2017 7:01 AM, Jostein wrote:

P.J.,

So if you just stand still there's no energy spent?

E = 2.268 kg x 9.81 N/kg x 0 m

:-)

Jostein


Den 25.06.2017 05.25, skrev P. J. Alling:
I don't think that the comparison works, exactly.  The amount of 
energy required to lift 5lbs 7 inches (about the height of a stair 
step), is pretty simple math but does involve knowing the energy 
needed to overcome the acceleration due to gravity in Newtons per 
kg,  which, I looked up, (you don't think I know this stuff off the 
top of my head), and convert pounds to kilograms and height to 
meters, but then all the terms just drop out and I can look up the 
values.


E = 2.268 kg x 9.81 N/kg x .1758 m

E = 3.9114 joules or if converted into food calories 9.3482 x 10^-4. 
Which is less than the calories you'd get from eating a stick of 
celery.  Assuming 15 stairs in a flight, about 9 feet between floors, 
I get .014 additional calories to climb a flight of stairs, with the 
extra 5 pound burden, assuming I did the math right.


However the actual stress on your body should be the same as just 
holding the extra 5 pounds and walking on the level, unless you've 
managed to somehow achieve multi g accelerations.


If you're having trouble getting enough oxygen it might feel like the 
extra 5 pounds gains weight while you're climbing stairs.



On 6/24/2017 12:33 PM, ann sanfedele wrote:
What is the difference in virtual weight of a pack (say, ten lbs) 
being carried bys omeone walking on level ground and the same person 
carrying

the same pack up a flight of stairs?

I'm sure I'm not using the corrrect terms here, I"m sure but I'm 
looking for the as if  related to the stress it puts on my body.


Is it like I'm carrying 5 more lbs?  20 more lbs?  etc

answer ON list so ten people don't have to respond :-)

thanks, guys

ann









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Re: OT - "as if" physics question

[Sandy Harris]

On Sat, Jun 24, 2017 at 12:33 PM, ann sanfedele  wrote:

> What is the difference in virtual weight of a pack (say, ten lbs) being
> carried bys omeone walking on level ground and the same person carrying
> the same pack up a flight of stairs?
>
> I'm sure I'm not using the corrrect terms here, I"m sure but I'm looking for
> the as if  related to the stress it puts on my body.
>
> Is it like I'm carrying 5 more lbs?  20 more lbs?  etc

I cannot answer that & am not sure anything meaningful can be
calculated in those terms. But here's some stuff I do know in case it
is helpful.

The effort required to get up the stairs is in direct proportion to
weight, so for example a 100-pound woman carrying a 10-pound pack
works 10% harder than she would climbing the same stairs without the
pack.

The work done is that effort multiplied by the height it travels
through, so for example hauling it up a 12' staircase is four times as
much work as lifting it 3' to hang the bag at your hip. That work
becomes potential energy which you get back going down, so for example
if you drop the bag off a 12' balcony there is four times the
lens-shattering energy you'd get dropping it from your hip.

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Re: OT - "as if" physics question

[Jostein]

P.J.,

So if you just stand still there's no energy spent?

E = 2.268 kg x 9.81 N/kg x 0 m

:-)

Jostein


Den 25.06.2017 05.25, skrev P. J. Alling:
I don't think that the comparison works, exactly.  The amount of energy 
required to lift 5lbs 7 inches (about the height of a stair step), is 
pretty simple math but does involve knowing the energy needed to 
overcome the acceleration due to gravity in Newtons per kg,  which, I 
looked up, (you don't think I know this stuff off the top of my head), 
and convert pounds to kilograms and height to meters, but then all the 
terms just drop out and I can look up the values.


E = 2.268 kg x 9.81 N/kg x .1758 m

E = 3.9114 joules or if converted into food calories 9.3482 x 10^-4. 
Which is less than the calories you'd get from eating a stick of 
celery.  Assuming 15 stairs in a flight, about 9 feet between floors, I 
get .014 additional calories to climb a flight of stairs, with the extra 
5 pound burden, assuming I did the math right.


However the actual stress on your body should be the same as just 
holding the extra 5 pounds and walking on the level, unless you've 
managed to somehow achieve multi g accelerations.


If you're having trouble getting enough oxygen it might feel like the 
extra 5 pounds gains weight while you're climbing stairs.



On 6/24/2017 12:33 PM, ann sanfedele wrote:
What is the difference in virtual weight of a pack (say, ten lbs) 
being carried bys omeone walking on level ground and the same person 
carrying

the same pack up a flight of stairs?

I'm sure I'm not using the corrrect terms here, I"m sure but I'm 
looking for the as if  related to the stress it puts on my body.


Is it like I'm carrying 5 more lbs?  20 more lbs?  etc

answer ON list so ten people don't have to respond :-)

thanks, guys

ann






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Re: OT - "as if" physics question

[Jostein]

Den 25.06.2017 04.04, skrev P. J. Alling:

E = mc^2  probably comes into it somewhere...


Oh geez,  I hope not, or else Ann is atomic powered.


We all are, P.J.
What we don't want is to convert Ann from mass to energy. :-)

Jostein

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Re: OT - "as if" physics question

[P. J. Alling]

I don't think that the comparison works, exactly.  The amount of energy 
required to lift 5lbs 7 inches (about the height of a stair step), is 
pretty simple math but does involve knowing the energy needed to 
overcome the acceleration due to gravity in Newtons per kg,  which, I 
looked up, (you don't think I know this stuff off the top of my head),   
and convert pounds to kilograms and height to meters, but then all the 
terms just drop out and I can look up the values.


E = 2.268 kg x 9.81 N/kg x .1758 m

E = 3.9114 joules or if converted into food calories 9.3482 x 10^-4.  
Which is less than the calories you'd get from eating a stick of 
celery.  Assuming 15 stairs in a flight, about 9 feet between floors, I 
get .014 additional calories to climb a flight of stairs, with the extra 
5 pound burden, assuming I did the math right.


However the actual stress on your body should be the same as just 
holding the extra 5 pounds and walking on the level, unless you've 
managed to somehow achieve multi g accelerations.


If you're having trouble getting enough oxygen it might feel like the 
extra 5 pounds gains weight while you're climbing stairs.



On 6/24/2017 12:33 PM, ann sanfedele wrote:
What is the difference in virtual weight of a pack (say, ten lbs) 
being carried bys omeone walking on level ground and the same person 
carrying

the same pack up a flight of stairs?

I'm sure I'm not using the corrrect terms here, I"m sure but I'm 
looking for the as if  related to the stress it puts on my body.


Is it like I'm carrying 5 more lbs?  20 more lbs?  etc

answer ON list so ten people don't have to respond :-)

thanks, guys

ann




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Re: OT - "as if" physics question

[P. J. Alling]

E = mc^2  probably comes into it somewhere...


Oh geez,  I hope not, or else Ann is atomic powered.


On 6/24/2017 1:31 PM, Bob W-PDML wrote:

The mass of the pack doesn't change, but as you step up you are having to lift 
with each leg in turn your own mass plus the mass of the pack, which you are 
not having to do, to the same extent, when you walk on level ground, so you are 
using more energy.

To convert it to additional weight I suppose you have to work out how much 
extra weight would require the same energy over the same distance on level 
ground.

E = mc^2 probably comes into it somewhere...

Whether it stresses the body in the same way would be something else though, 
because the biomechanics of carrying it upstairs are different to those of 
carrying it on level ground.

My answer would be to order a Sherpa...


On 24 Jun 2017, at 17:34, ann sanfedele  wrote:

What is the difference in virtual weight of a pack (say, ten lbs) being carried 
bys omeone walking on level ground and the same person carrying
the same pack up a flight of stairs?

I'm sure I'm not using the corrrect terms here, I"m sure but I'm looking for 
the as if  related to the stress it puts on my body.

Is it like I'm carrying 5 more lbs?  20 more lbs?  etc

answer ON list so ten people don't have to respond :-)

thanks, guys

ann

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Re: OT - "as if" physics question

[ann sanfedele]

Actually, I won't be taking advantage of that caolorie burning potential 
increase very often, because it will wreck my knee joints and spine.

as earlier mentioned, I do have sherpas

ann

On 6/24/2017 8:50 PM, Jostein wrote:
Came to the same result as Bill on the added calories needed to bring 
the pack up one flight of stairs. But that's just the extra energy now 
"stored" in the package as potential energy.


A backwards trace of the energy could look something like this:

To transfer the energy to the package, your muscles has to do work. 
Muscles are machines that convert some of its fuel to work, and some 
to heat. So the energy for both must come from food, which is where we 
usually count calories.


So the number of calories you need to ingest to perform the work is 
far greater than Newtonian physics will have you believe from the 
perspective of the package. :-)


Jostein

Den 24.06.2017 23.50, skrev ann sanfedele:

Thanks all you smart gents

arrrgh - I answered  Bob, and Jack and  you hitting "reply" I just 
noticed


all interesting answers  but yours was the one I like best , if your 
math _is_ right -  it sure FEELS like it...


10 ft celings here - no wonder I'm maintaing my relative svelt 
dimensions :-)


a

On 6/24/2017 4:41 PM, William Robb wrote:
On Sat, Jun 24, 2017 at 10:34 AM ann sanfedele  
wrote:


What is the difference in virtual weight of a pack (say, ten lbs) 
being
carried bys omeone walking on level ground and the same person 
carrying

the same pack up a flight of stairs?


It's 42.

Actually, it's about 32.4 calories to carry 10 pounds up a flight of 
stairs

presuming 10' from floor to floor.

Bill



I'm sure I'm not using the corrrect terms here, I"m sure but I'm 
looking

for the as if  related to the stress it puts on my body.

Is it like I'm carrying 5 more lbs?  20 more lbs?  etc

answer ON list so ten people don't have to respond :-)

thanks, guys

ann

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Re: OT - "as if" physics question

[Jostein]

Came to the same result as Bill on the added calories needed to bring 
the pack up one flight of stairs. But that's just the extra energy now 
"stored" in the package as potential energy.


A backwards trace of the energy could look something like this:

To transfer the energy to the package, your muscles has to do work. 
Muscles are machines that convert some of its fuel to work, and some to 
heat. So the energy for both must come from food, which is where we 
usually count calories.


So the number of calories you need to ingest to perform the work is far 
greater than Newtonian physics will have you believe from the 
perspective of the package. :-)


Jostein

Den 24.06.2017 23.50, skrev ann sanfedele:

Thanks all you smart gents

arrrgh - I answered  Bob, and Jack and  you hitting "reply" I just noticed

all interesting answers  but yours was the one I like best , if your 
math _is_ right -  it sure FEELS like it...


10 ft celings here - no wonder I'm maintaing my relative svelt 
dimensions :-)


a

On 6/24/2017 4:41 PM, William Robb wrote:

On Sat, Jun 24, 2017 at 10:34 AM ann sanfedele  wrote:


What is the difference in virtual weight of a pack (say, ten lbs) being
carried bys omeone walking on level ground and the same person carrying
the same pack up a flight of stairs?


It's 42.

Actually, it's about 32.4 calories to carry 10 pounds up a flight of 
stairs

presuming 10' from floor to floor.

Bill



I'm sure I'm not using the corrrect terms here, I"m sure but I'm looking
for the as if  related to the stress it puts on my body.

Is it like I'm carrying 5 more lbs?  20 more lbs?  etc

answer ON list so ten people don't have to respond :-)

thanks, guys

ann

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Re: OT - "as if" physics question

[ann sanfedele]

 So Wheatfield and you disagree on the degree, as it were...

Thanks for chiming in - I see you are still alive :-)
ann

On 6/24/2017 4:17 PM, J.C. O'Connell wrote:
its as if you added 10 extra pounds, its just more work because its 
uphill

just like walking upstairs is more work for your normal weight.



On Sat, 24 Jun 2017 16:02:19 -0400, Ken Waller <kwal...@peoplepc.com> 
wrote:






-Original Message-

From: David J Brooks <pentko...@gmail.com>
Subject: Re: OT - "as if" physics question

Is it an African package or European package.:-)


And are you migrating



Dave

On Sat, Jun 24, 2017 at 12:33 PM, ann sanfedele <ann...@nyc.rr.com> 
wrote:
What is the difference in virtual weight of a pack (say, ten lbs) 
being
carried bys omeone walking on level ground and the same person 
carrying

the same pack up a flight of stairs?

I'm sure I'm not using the corrrect terms here, I"m sure but I'm 
looking for

the as if  related to the stress it puts on my body.

Is it like I'm carrying 5 more lbs?  20 more lbs?  etc

answer ON list so ten people don't have to respond :-)

thanks, guys

ann

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Re: OT - "as if" physics question

[ann sanfedele]

Thanks all you smart gents

arrrgh - I answered  Bob, and Jack and  you hitting "reply" I just noticed

all interesting answers  but yours was the one I like best , if your 
math _is_ right -  it sure FEELS like it...


10 ft celings here - no wonder I'm maintaing my relative svelt 
dimensions :-)


a

On 6/24/2017 4:41 PM, William Robb wrote:

On Sat, Jun 24, 2017 at 10:34 AM ann sanfedele  wrote:


What is the difference in virtual weight of a pack (say, ten lbs) being
carried bys omeone walking on level ground and the same person carrying
the same pack up a flight of stairs?


It's 42.

Actually, it's about 32.4 calories to carry 10 pounds up a flight of stairs
presuming 10' from floor to floor.

Bill



I'm sure I'm not using the corrrect terms here, I"m sure but I'm looking
for the as if  related to the stress it puts on my body.

Is it like I'm carrying 5 more lbs?  20 more lbs?  etc

answer ON list so ten people don't have to respond :-)

thanks, guys

ann

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Re: OT - "as if" physics question

[William Robb]

On Sat, Jun 24, 2017 at 10:34 AM ann sanfedele  wrote:

> What is the difference in virtual weight of a pack (say, ten lbs) being
> carried bys omeone walking on level ground and the same person carrying
> the same pack up a flight of stairs?


It's 42.

Actually, it's about 32.4 calories to carry 10 pounds up a flight of stairs
presuming 10' from floor to floor.

Bill

>
>
> I'm sure I'm not using the corrrect terms here, I"m sure but I'm looking
> for the as if  related to the stress it puts on my body.
>
> Is it like I'm carrying 5 more lbs?  20 more lbs?  etc
>
> answer ON list so ten people don't have to respond :-)
>
> thanks, guys
>
> ann
>
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Re: OT - "as if" physics question

[J.C. O'Connell]

its as if you added 10 extra pounds, its just more work because its uphill
just like walking upstairs is more work for your normal weight.



On Sat, 24 Jun 2017 16:02:19 -0400, Ken Waller <kwal...@peoplepc.com>  
wrote:






-Original Message-

From: David J Brooks <pentko...@gmail.com>
Subject: Re: OT - "as if" physics question

Is it an African package or European package.:-)


And are you migrating



Dave

On Sat, Jun 24, 2017 at 12:33 PM, ann sanfedele <ann...@nyc.rr.com>  
wrote:

What is the difference in virtual weight of a pack (say, ten lbs) being
carried bys omeone walking on level ground and the same person carrying
the same pack up a flight of stairs?

I'm sure I'm not using the corrrect terms here, I"m sure but I'm  
looking for

the as if  related to the stress it puts on my body.

Is it like I'm carrying 5 more lbs?  20 more lbs?  etc

answer ON list so ten people don't have to respond :-)

thanks, guys

ann

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Re: OT - "as if" physics question

[Ken Waller]

-Original Message-
>From: David J Brooks <pentko...@gmail.com>
>Subject: Re: OT - "as if" physics question
>
>Is it an African package or European package.:-)

And are you migrating 


>Dave
>
>On Sat, Jun 24, 2017 at 12:33 PM, ann sanfedele <ann...@nyc.rr.com> wrote:
>> What is the difference in virtual weight of a pack (say, ten lbs) being
>> carried bys omeone walking on level ground and the same person carrying
>> the same pack up a flight of stairs?
>>
>> I'm sure I'm not using the corrrect terms here, I"m sure but I'm looking for
>> the as if  related to the stress it puts on my body.
>>
>> Is it like I'm carrying 5 more lbs?  20 more lbs?  etc
>>
>> answer ON list so ten people don't have to respond :-)
>>
>> thanks, guys
>>
>> ann
>>
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>-- 
>Documenting Life in Rural Ontario.
>www.caughtinmotion.com
>http://brooksinthecountry.blogspot.com/
>York Region, Ontario, Canada

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Re: OT - "as if" physics question

[David J Brooks]

Is it an African package or European package.:-)

Dave

On Sat, Jun 24, 2017 at 12:33 PM, ann sanfedele  wrote:
> What is the difference in virtual weight of a pack (say, ten lbs) being
> carried bys omeone walking on level ground and the same person carrying
> the same pack up a flight of stairs?
>
> I'm sure I'm not using the corrrect terms here, I"m sure but I'm looking for
> the as if  related to the stress it puts on my body.
>
> Is it like I'm carrying 5 more lbs?  20 more lbs?  etc
>
> answer ON list so ten people don't have to respond :-)
>
> thanks, guys
>
> ann
>
> --
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> http://pdml.net/mailman/listinfo/pdml_pdml.net
> to UNSUBSCRIBE from the PDML, please visit the link directly above and
> follow the directions.



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Documenting Life in Rural Ontario.
www.caughtinmotion.com
http://brooksinthecountry.blogspot.com/
York Region, Ontario, Canada

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Re: OT - "as if" physics question

[Jack Davis]

You have defined why one would tire
when walking if each step represented a lift rather than that
required on a level surface.

J

Sent from my iPhone

> On Jun 24, 2017, at 10:31 AM, Bob W-PDML  wrote:
> 
> The mass of the pack doesn't change, but as you step up you are having to 
> lift with each leg in turn your own mass plus the mass of the pack, which you 
> are not having to do, to the same extent, when you walk on level ground, so 
> you are using more energy.
> 
> To convert it to additional weight I suppose you have to work out how much 
> extra weight would require the same energy over the same distance on level 
> ground.
> 
> E = mc^2 probably comes into it somewhere...
> 
> Whether it stresses the body in the same way would be something else though, 
> because the biomechanics of carrying it upstairs are different to those of 
> carrying it on level ground.
> 
> My answer would be to order a Sherpa...
> 
>> On 24 Jun 2017, at 17:34, ann sanfedele  wrote:
>> 
>> What is the difference in virtual weight of a pack (say, ten lbs) being 
>> carried bys omeone walking on level ground and the same person carrying
>> the same pack up a flight of stairs?
>> 
>> I'm sure I'm not using the corrrect terms here, I"m sure but I'm looking for 
>> the as if  related to the stress it puts on my body.
>> 
>> Is it like I'm carrying 5 more lbs?  20 more lbs?  etc
>> 
>> answer ON list so ten people don't have to respond :-)
>> 
>> thanks, guys
>> 
>> ann
>> 
>> -- 
>> PDML Pentax-Discuss Mail List
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>> http://pdml.net/mailman/listinfo/pdml_pdml.net
>> to UNSUBSCRIBE from the PDML, please visit the link directly above and 
>> follow the directions.
> 
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Re: OT - "as if" physics question

[Bob W-PDML]

There are some equations on this site, related to bicycles, but similar 
question. I leave it as an exercise for the reader to rearrange the terms 
appropriately, since I've never studied physics.

https://bicycles.stackexchange.com/questions/13090/extra-power-needed-uphill-for-weight-increase

B

On 24 Jun 2017, at 18:32, Bob W-PDML 
> wrote:

The mass of the pack doesn't change, but as you step up you are having to lift 
with each leg in turn your own mass plus the mass of the pack, which you are 
not having to do, to the same extent, when you walk on level ground, so you are 
using more energy.

To convert it to additional weight I suppose you have to work out how much 
extra weight would require the same energy over the same distance on level 
ground.

E = mc^2 probably comes into it somewhere...

Whether it stresses the body in the same way would be something else though, 
because the biomechanics of carrying it upstairs are different to those of 
carrying it on level ground.

My answer would be to order a Sherpa...

On 24 Jun 2017, at 17:34, ann sanfedele 
> wrote:

What is the difference in virtual weight of a pack (say, ten lbs) being carried 
bys omeone walking on level ground and the same person carrying
the same pack up a flight of stairs?

I'm sure I'm not using the corrrect terms here, I"m sure but I'm looking for 
the as if  related to the stress it puts on my body.

Is it like I'm carrying 5 more lbs?  20 more lbs?  etc

answer ON list so ten people don't have to respond :-)

thanks, guys

ann

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Re: OT - "as if" physics question

[Bob W-PDML]

The mass of the pack doesn't change, but as you step up you are having to lift 
with each leg in turn your own mass plus the mass of the pack, which you are 
not having to do, to the same extent, when you walk on level ground, so you are 
using more energy.

To convert it to additional weight I suppose you have to work out how much 
extra weight would require the same energy over the same distance on level 
ground.

E = mc^2 probably comes into it somewhere...

Whether it stresses the body in the same way would be something else though, 
because the biomechanics of carrying it upstairs are different to those of 
carrying it on level ground.

My answer would be to order a Sherpa...

> On 24 Jun 2017, at 17:34, ann sanfedele  wrote:
> 
> What is the difference in virtual weight of a pack (say, ten lbs) being 
> carried bys omeone walking on level ground and the same person carrying
> the same pack up a flight of stairs?
> 
> I'm sure I'm not using the corrrect terms here, I"m sure but I'm looking for 
> the as if  related to the stress it puts on my body.
> 
> Is it like I'm carrying 5 more lbs?  20 more lbs?  etc
> 
> answer ON list so ten people don't have to respond :-)
> 
> thanks, guys
> 
> ann
> 
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Re: OT - "as if" physics question

[Jack Davis]

Same gravity, each step up
represents a sense of it's
pull.

J

Sent from my iPhone

> On Jun 24, 2017, at 9:33 AM, ann sanfedele  wrote:
> 
> What is the difference in virtual weight of a pack (say, ten lbs) being 
> carried bys omeone walking on level ground and the same person carrying
> the same pack up a flight of stairs?
> 
> I'm sure I'm not using the corrrect terms here, I"m sure but I'm looking for 
> the as if  related to the stress it puts on my body.
> 
> Is it like I'm carrying 5 more lbs?  20 more lbs?  etc
> 
> answer ON list so ten people don't have to respond :-)
> 
> thanks, guys
> 
> ann
> 
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> http://pdml.net/mailman/listinfo/pdml_pdml.net
> to UNSUBSCRIBE from the PDML, please visit the link directly above and follow 
> the directions.


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