Kind: captions
Language: en
an apple weighs about 1 Newton the world
record for jet engine thrust is 570,000
Newtons and the Saturn 5 rocket that
launched people to the Moon had a Thrust
of
33,36 th000 Newtons but how can we
measure forces this big
accurately well we need to ask this guy
uh hi my name's Rick cyer I'm a physical
scientist in the mass en Force group am
I supposed to look at the camera sure
okay you look at anything you like yeah
Rick manages a dead weight machine that
can apply
4,448 222 Newtons why such a strange
number because that's exactly equal to 1
million PB of force there are 20 50
50,000 lb increments in this machine 20
* 50 = 1 million PB cumulatively that's
4.45 Mega newon elsewhere in the world
are there larger masses that people have
calibrated I asked that question to
every visitor we get and I've not gotten
one response that says yeah I know where
bigger stuff is calibrated so if I
really want to go out and a Limon brag
I'll say these are the largest mass
objects ever
calibrated anywhere the machine works
like this below ground are the 20
carefully calibrated masses their weight
is used to calibrate four sensors also
called force transducers in the lab
upstairs this is a 1 million pound
capacity 4.45 meon and this is 13.3
megon 3 million PBS Force
this is the biggest machine of this of
its type in the world and uh uh
obviously One of a Kind one of these
would be placed on the compression head
right here then a hydraulic ram in the
Attic starts to raise the green lifting
frame and once the force transducer
contacts the red loading frame well then
it starts lifting the weights downstairs
and as the lifting frame continues to
rise more and more of the 50,000 lb
weights become suspended by the force
sensor and since the weights create an
accurately known Force the readouts from
the force transducer can be precisely
calibrated these devices are then sent
out into the field well literally
literally there's a test stand that's
set up with one of these gizmos a force
transducers embedded in a test stand
somewhere fire and we have ignition of
NASA's space launch system solid rocket
motor powering us on our Journey to Mars
and so the rocket is fired up perh half
ramped up ramped down and those forces
are monitored you know the old the old
moov to hear oh go to 104% of power well
how do they know it's 104% of power
because somebody's measured it somewhere
when it comes to minimizing uncertainty
these guys aren't messing around this
piece right here is approximately ,36
[Laughter]
just a few American nickels yeah or the
difference yeah that tiny uncertainty is
measured with respect to the very
definition of the kilogram using K20
that's the United States fundamental
Mass standard this is done by comparing
combinations of known weights starting
with K20 with larger unknown weights
gradually working up to larger and
larger masses for example here a single
5 kg mass is compared to two twos and a
one at some point in this process they
convert and start working in pounds
going from 50 lb masses to 500 lb and
then 2500 lb and then using a scale in
the floor to reach 10,000 lb and then
20,000 and finally 30,000 lb
combinations of these huge weights are
then used to calibrate the 50,000 lb
masses which form the weight stack and
we have to have that because what we
sell is the vertical Force Vector that's
generated by these weights hanging in
the gravitational field we sell that
with an uncertain attached to it of
0.5% 5 part per a million so that means
at full 1 million PB of applied force we
guarantee that to be accurate if you
will within 5 lbs not only does that
mean the masses have to be accurately
calibrated it also means the
gravitational acceleration at this
location has to be taken into account is
actually slightly less than Earth's
standard gravity so an additional 600 lb
are required plus the buoyant force must
be counteracted since these masses
displace 125 lbs of air a further 125 lb
must be added to reach a million pounds
of force what what strikes me as kind of
amazing is that like this machine needs
to exist in a way like yeah when I when
I would have thought about it like how
would Boeing measure its forces I would
have thought okay they just you know
calibrate a device that works you know
up to X but then they can you know
generalize well generalize you know what
I mean like yes there there's an AC that
says um one physical test is worth a
th000 expert
opinions and that has proven itself time
and again particularly in the world of
physical testing if you're getting on an
airplane that somebody has built are you
willing to accept a 10% uncertain on
these numbers or do you want it to be
the uncertainty of these measurements to
be down in the
mud I think that's what you want tick
tock
tick
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