Apparently according to F=ma, no. It wouldn't get rotational kinetic
energy, it would get translational kinetic energy just the same as
if it'd been hit in line with its center of mass. This goes contrary to
daily experience and intuition - maybe because objects in our daily lives
are acted on by frictional forces that are cause a torque when they're hit
with a glancing blow.
what think?
laura
Yes.
>
> Apparently according to F=ma, no.
The glancing blow induces a torque, which
causes angular acceleration. The angular equivalent of
F = ma is T = I*alpha.
> It wouldn't get rotational kinetic
> energy, it would get translational kinetic energy just the same as
> if it'd been hit in line with its center of mass. This goes contrary to
> daily experience and intuition - maybe because objects in our daily lives
> are acted on by frictional forces that are cause a torque when they're hit
> with a glancing blow.
It doesn't require friction. Just, as you say, a torque.
- Randy
2.5 billion years ago? or 4.4 Gyrs ago?
That point right there is your mistake. F=ma only addresses the linear
motion and not the rotational motion (the rotational analog to F=ma
does). F=ma does apply but it is not the only law that pertains here.
Now, you may be right in asking, "What about all those problems where
all we used was F=ma and we paid no attention to the other laws that
may or may not pertain? Was that wrong?"
No, not necessarily, but you *are* making an explicit assumption that
you are willing to neglect those other aspects of the motion.
A good example is the stopping of a car, a common problem in beginning
physics. F=ma might eventually tell you how long it takes for a car to
stop, but you know that a car pitches forward when braking, too, and
this was neglected in calculating the distance to stop.
PD
It all depends on the shape of the rock and where it is being hit:
if the local vertical at the point of impact passes through the center
of mass, then there will be no torque exerted and thus the rock will
not rotate at all. The more the local vertical misses the center of
mass, the higher the torque and the more the rock will rotate. A
spherical rock would thus not rotate at all (assuming a fully elastic
collision) as all local verticals pass through the center of mass of a
sphere.
I found a nice Java applet which simulates colliding blocks and shows
how this affects the translational and rotational motion (
http://www.myphysicslab.com/collision.html ).
Thomas
I said this because when you have a rigid body, for F=ma, to find the
acceleration of the center of mass, it doesn't matter where the external
forces are applied, whether they're in line with the center of mass or
not. So it seemed like the glancing blow would give the center of mass
the same acceleration as a blow on the center, and presumably no rotation.
But I calculated what happens if you hit a rod with a ball moving
perpendicular to the rod. If the ball hits the rod in the center, it
gives all of its kinetic energy to the rod, which gets translational
kinetic energy and doesn't rotate.
But if the ball hits the rod at the end - the glancing blow of the title -
the force isn't the same! Because the rod "moves out of the way". The
ball doesn't give up all its kinetic energy, it keeps on moving. The
center of mass of the rod moves a little, it gets 2/5 of the velocity of
the ball. The rod starts spinning.
Laura
2.5 billion years ago? or 4.4 Gyrs ago?
Herbie, your pain meds are doing this to you, not me. Or maybe
there is the possibility that your Zionist fanaticism is causing your
aberrant condition and your out-bursts. So, have a ham sandwich
and plenty of crispy pork rind with a good Lager to ameliorate
your self-destructive state of mind and body.... because....
ahahahaha... see Herbie, you are so far gone in your Zionist pan-
hatred & your delusions that you just can't accept reality any longer.
El is not Head of DHS but he is station chief of DHS in the port of
Alexandria in Egypt. (Well paid too. $150k/year plus free flying)
Look up the appropriate web page, olde kacker. Here's the link for
DHS in www.dhs.gov/ and you can see his name right in there:
"Prof. Dr. Hemet Shokry Isaac El Sharony" ... ahahahaha...
BTW, go and read his posts and see that EL is really a Jew, a
good one at that. Here see and read for yourself, olde kacker:
http://groups.google.fr/group/sci.archaeology/msg/4ce6d9ae701dd19d
Zion-Glaser listen, you are not only an extreme embarrassment to
the Jewish community but you are one of those Jews that create &
promulgate Anti-Semitism. Yes you, a Jew promotes Anti-Semitism,
big time, like a few others did here in these NGs, especially Kolker.
http://groups.google.com/group/sci.physics/msg/96806240eaf4d542
wherein ersatz rabbi Robert J. Kolker says:
BK::: The obvious solution is to kill them all and let Allah sort
BK::: out the good from the bad. .... In the US we can expell the
BK::: foreign born moslems to a convenient killing field and
BK::: vet the remaining ones. .... we have to kill them all overseas
BK::: and herd the domestic Moslems into controlled areas....
BK::: We can also take their youngest children to be raised properly
BK::: and sterilize the rest. The problem will be completely solved in
BK::: about 70 years.
http://groups.google.com/group/sci.astro/msg/82caaf5ff6e0038c
BK::: I advocate wide scale genocide on the Moslems.
... and also urges in news:2rfqqdF...@uni-berlin.de on 09-23-04,
BK::: to put all Xians into asylums for their belief in Christianity.
>
See Herbie, what company you are riding with? You Jews have a
Final Solution for your objects of hate, exactly like Hitler did. Now
why should that make you any better then the Islamo-fascists or
Moslem-terrorists who want Israel be wiped off the map? All you
fuckers richly deserve each other in your self-destructive ways.
However, remember, Herbie, there are only a few of you, but there
are vast legions of them. Demography does not bode well for
you. Check it out, Herbie, and then you can cry with justification:
"sad but true"... ahahaha...
... as bad as you two Abe spawns are so are the Evangelicals
of the Armageddon lobby in the US who fan the flames between
you Jews and the Muslims in the hope of accelerating the
"Second Coming" of Jesus Christ... ahahahaha...
Now, can't you see, Hebie, how for some self-destructive reason
you, like a bunch of other Jews, are in workin so very hard to make
Hitler's last curse last curse to become a self-filling prophesy which
Hitler broadcast just before his demise in 45, in which he said:....
"in a 100 years from now the world will be grateful for what I have
started". ---- Herbie... 61 down... 39 to go... and it looks like you
Jews are right on track.... ahahahaha....
Glaser, it was you Zionists alone who have laid the ground work
to rail up first the Palis, then the entire Middle East, then the whole
global fucking Muslim world against the West & dragging the US
into this unholy shit we are in today. Naturally now, that the water is
up to your ears... you loudly whine and your Jew organizations
show KZ Films again all evening long every week on TV in the US
hoping to stir up pity and support..... and inadvertently generating
more Anti-Semitism in the process... because it was not Amis
who gassed the Jews. So, why rub it into us US citizens in your
desperation hoping to make us feel guilty when we give you already
$$$$ 3 Billion dollars every year each year for the last 50 years
and all we get of you in return is war and mayhem because of you?
But because of your loudmouthed hatred, fanaticism & megalomania
you don't wanna hear the naked truth and you have become too blind
to see and notice how subtle and widespread Anti-Semitism has
become in the US.... to wit as of late: Gibson and even O'Reilly
exudes frequent Freudian slips letting his disdain shine thru for
loud Jews like you and your Zionist ilk. Can't you see the hand
writing on the wall any longer, olde kacker?..... Your B'nai Brith
bitterly whined in 2005 that there were 300'000 fever Jews in the
year 2000, in the US, then there were in 1970. It was on CNN for
a whole week. These were the smart and decent Jews.
You are not one of them.... obviously.... ahahahaha...
Never the less Hebie, Thanks for the laughs..... ahahaha....
ahahaha.... ahahanson
Yes, this is all absolutely right, but you are now jumbling several
different things together: kinetic energy, momentum, and Newton's 2nd
law.
You are making the assumption that if the same ball is used in both
cases, then the force F should be the same in both cases. This is
simply not the case.
The force F is proportional to the *change* in momentum, or if you
like, the linear momentum imparted from the ball to the rod.
What you have found is that less linear momentum is transferred from
the ball to the rod if the ball hits the rod at the end, compared to if
the ball hits the rod at the center. This of course means that the
force F is also different.
What is still true, however, are the following facts:
a) the linear acceleration of the rod is given by F = m*a, where F is
the force applied by the ball on the rod.
b) the rotational acceleration of the rod is given by T = I*alpha,
where T is the torque applied by the ball on the rod.
c) the linear momentum of the rod plus ball is the same before and
after the collision, and this is true in both cases.
d) the rotational momentum of the rod plus ball is the same before and
after the collision, and this is true in both cases.
e) the kinetic energy of the ball gets converted into linear kinetic
energy of the rod plus rotational kinetic energy of the rod plus
lineear kinetic energy of the ball.
PD
Androcles
That depends. At the moment of impact the momentum of the second
rock is in a direction parallel to its motion and acting at a point on
the surface of the first rock. Only if the momentum vector is
perfectly
aligned with the *center of mass* of the first rock will the second
rock
apply *no* torque at impact. No torque means no resulting rotation.
Otherwise, there *will* be rotation.
Tom Davidson
Richmond, VA
I don't mind if you Jews finance and protect Israel with Jewish
money. That's ok by me. That is your, a sole Jewish, affair. Cool!.
But don't force and drag the rest of the US population continuously
into your Jew-shit and make them pay for it... So, Zion Herbie, tell
me what it is that you are going to do for me with your helping hands....
I prefer $ instead of your hands.... anytime, anywhere... ahaha...
>
[Zion Herbie]
its nice to be nice.
>
[hanson]
ahahaha... then show me that you are nice, Herbie, and help yourself
by you stopping with your phony harping. .... You have conveniently
"forgotten" that YOU started this out of the blue and now you wish to
obfuscate it with your self-anointments... which is why I reposted the
whole "schmier" again.... ahahaha... It's for your benefit, Zion Herbie.
>
[Zion Herbie]
> I can't keep answering your posts,for it takes my mind off of science,
> [ahaha.. your mind and science... ahaha]... and this is a science group.
> My advice to you is to find a group on religions, for hating each
> other's Gods fits well with your hateful thinking mind Bert
>
[hanson]
ahahahaha.. Better advise yourself first and foremost, because ** YOU **
started all this, Zion Herbie, not me. YOU dragged the discussion from
cosmology angrily into the realm of politics without cause. Here check it:
H: http://groups.google.com/group/sci.physics/msg/b66d4b6f1d2df68f
Z: http://groups.google.com/group/sci.physics/msg/42383898f3d43a69
If you want this thread to end then don't respond and take YOUR own
advice and take YOUR posts about YOUR religion into groups other then
here. Zion-Herbie, look at your own record in sci.* before you cast stones:
google/groups: 288 hits for --[author:"G=EMC^2 Glazier" & God]--
google/groups: 222 hits for --[author:"G=EMC^2 Glazier" & hate]--
... See "caveat" at the end of this post .....
>
[hanson prior]
Herbie anointed himself with "I am a nice person" in his previous post:
http://groups.google.com/group/sci.physics/msg/36853b511e58e660
He very carefully avoids to mention that he is a Zionist ... ahahahaha....
But, Zion Herbie showed what kind of "nice person" is REALLY is when
he was telling me that: "Six years after you are dead people will piss on
your grave", etc, etc... ahahahaha... making himself, Zion Herbie, to fit
right into the mold of the stereotype Jew. And the problem with stereotypes
is that they are true... ahahahaha... The reason that all this is so
hilarious is because Zion Hebie got so discombobulated and bent
himself out of shape when he strenuously generated, produced,
precipitated, fomented and promulgated heaps of new Anti-Semitism...
in a classical event development pictured here in his posts following
below:
>
ahahahaha...ahahahaha... AHAHAHAHA... ahahahaha....ahahahaha.
Zion-Glaser aka "G=EMC^2 Glazier" <herbert...@webtv.net>
who is a self-admitted Grave-Vandal and who yearns to piss on
peoples' graves has the chutzpah, as his ilk would say, to moralize in his
news:6395-44D...@storefull-3333.bay.webtv.net..
>
[Zion Herbie prior]
> Hanson To sum you up "You are an embarasment to all of humankind".
> You have no morals. Would rather hate than love. You would rather stab
> a person in the back than look them in the eye. You pull wings off flies.
> Sad but so very true Bert
>
[hanson prior]
ahahahaha... AHAHAHAHA... ahahahaha....ahahahaha... In typical Zionist
fashion "G=EMC^2 Zion Glazier" <herbert...@webtv.net> gets mad at
me in his news:9445-44D7...@storefull-3334.bay.webtv.net...
because I reminded Zion Herbie that El had posted that Zion Herbie was
an intellectual midget and the shepherd of his 12 years old cockroach...
ahahaha ... which prompted a typical hate flare up in Zion Herbie that
revealed Zion Herbie's apparent yearning to be a necrophiliac with an
urge to vandalize graves... .
....You are an embarrassment to the Jewish community, Glaser.
<
[Zion Herbie prior]
> Hanson'Big Moe" had more brains than you,and the type of humankind you
> represent. He did not kill nor eat his ownkind. Big Moe has been dead
> for 6 years. He is remembered. Six years after you are dead people will
> piss on your grave. Bert
>
[hanson's prior post]
ahahahaha... AHAHAHAHA... ahahahaha....ahahahaha...
Poor Zion Herbie "G=EMC^2 Glazier" <herbert...@webtv.net> w/i
news:26827-44D...@storefull-3335.bay.webtv.net... & shows
that he has an EL fetish that overwhelms him so completely that it
gives him nightmares & negates the effects of Zion Herbie's Viagra
regimen. EL's ghost discombobulates Zion-Herbie so profusely that
he is not able to find El in www.dhs.gov/ and so he whines & shares
with us his dry wet-dream about his cockroach after he read this.....
>
[hanson]
>> No, Zion Herbie, El is not Head of DHS as you have assumed,
>> but Dr. Hemet El is station chief of DHS in the port of Alexandria
>> in Egypt. (Well paid too. $150k/year plus free flying. Not bad, huh)
>> Look up the appropriate web page, olde kacker. Here's the link for
>> DHS in www.dhs.gov/ and you can see his name right in there:
>> "Prof. Dr. Hemet Shokry Isaac El Sharony" ... ahahahaha...
>> BTW, go and read his post and see that EL is really a Jew, a
>> good one at that. Here, see and read for yourself, olde kacker:
http://groups.google.fr/group/sci.archaeology/msg/4ce6d9ae701dd19d
>
[Zion Glaser]
> Hanson Ha Ha Ha Ha EL is Jewish(like Hitler) If El is Jewish than I
> can believe you are a rabbi. If El is Jewish I will eat only "matzo
> balls,and chicken soup." Maybe the Israel's named their air-line after
> him for all the kind words and thoughts he has for their well being (oh
> ya) El is doing hard time and is not allowed out of his cell. In his
> cell there is only a 60w bulb,and no means to connect a computer. Sad
> but closer to the truth than your post about this terrorist. Ha ha ha
> El has only rice and water,and that is more than he deserves Bert
>
[hanson]
ahahaha.. So, big deal that you will eat "matzo balls and chicken soup"
You do that anyway, Zion Herbie... ahahaha... but it is apparent that
EL really cranked you because he posted that you were an intellectual
midget and the shepherd of your 12 years old cockroach... ahahaha .
Furthermore, Herbie, you are the only Jew who gets upset over your
fellow Jew EL's comments. Zion Herbie, you should not react like that.
You, Zion Herbie (even collectively), are such a small minority that you
should learn how to make friends instead of making enemies every-
where and all the time. But you, as an ingrained Zionist, do not wanna
hear nor do that... Hey, what do I care, it's your collective ass that
invites, got and gets those historic asskickings and barbequings...
ahahahaha.... ... to boot, Zionh Herbie, it looks like that you are still
cranking yourself over again about these two posts here..... ahahaha
http://groups.google.com/group/sci.physics/msg/e44fceda8c6d504c
http://groups.google.com/group/sci.physics/msg/96806240eaf4d542
Herbie, your pain meds are doing this to you, not me. Or maybe
there is the possibility that your Zionist fanaticism is causing your
aberrant condition and your out-bursts. So, have a ham sandwich
and plenty of crispy pork rind with a good Lager to ameliorate
your self-destructive state of mind and body.... because....
ahahahaha... see Herbie, you are so far gone in your Zionist pan-
hatred & your delusions that you just can't accept reality any longer.
Zion-Glaser listen, you are not only an extreme embarrassment to
the Jewish community but you are one of those Jews that create &
promulgate Anti-Semitism. Yes you, a Jew promotes Anti-Semitism,
big time, like a few others did here in these NGs, especially Kolker.
http://groups.google.com/group/sci.physics/msg/96806240eaf4d542
wherein ersatz rabbi Robert J. Kolker says:
BK::: The obvious solution is to kill them all and let Allah sort
BK::: out the good from the bad. .... In the US we can expell the
BK::: foreign born moslems to a convenient killing field and
BK::: vet the remaining ones. .... we have to kill them all overseas
BK::: and herd the domestic Moslems into controlled areas....
BK::: We can also take their youngest children to be raised properly
BK::: and sterilize the rest. The problem will be completely solved in
BK::: about 70 years.
http://groups.google.com/group/sci.astro/msg/82caaf5ff6e0038c
BK::: I advocate wide scale genocide on the Moslems.... and Bob
also urges in news:2rfqqdF...@uni-berlin.de on 09-23-04,
BK::: to put all Christians into asylums for their belief in Christianity.
>
See Herbie, what company you are riding with? You Jews have a
Final Solution for your objects of hate, exactly like Hitler did. Now
why should that make you any better then the Islamo-fascists or
Moslem-terrorists who want Israel to be wiped off the map? All you
fuckers richly deserve each other in your self-destructive ways.
To boot, remember, Herbie, there are only a "few" of you Yidds, but
there are vast legions of Allah ass-venters that come looking for you.
Demography does not bode well for you. Check it out, Herbie, and
then you can cry with justification: "sad but true"... ahahaha...
... as bad as you two Abraham spawns (Jews and Muslims) are,
equally bad or worse are the Evangelicals of the Armageddon lobby
in the US who fan the flames between you Jews and the Muslims
in the hope of accelerating the "Second Coming" of Jesus Christ...
ahahahaha... "sad but true", isn't it, Zion Herbie"?.....
Now, can't you see, Hebie, how for some self-destructive reason
you are, like a bunch of other Jews, who working so very hard to
make Hitler's last curse last curse to become a self-filling prophesy
which Hitler broadcast just before his demise in 45, in which he said:....
"in a 100 years from now the world will be grateful for what I have
started". ---- Herbie... 61 down... 39 to go... and it looks like you
Jews are right on track.... ahahahaha....
Glaser, it was you Zionists alone who have laid the ground work
to rail up first the Palis, then the entire Middle East, then the whole
global fucking Muslim world against the West & dragging the US
into this unholy shit we are in today. Naturally now, that the water is
up to your ears... you loudly whine and your Jew organizations
show KZ Films again all evening long every week on TV in the US
hoping to stir up pity and support..... and inadvertently generating
more Anti-Semitism in the process... because it was not us Amis
who gassed the Jews. So, why rub it into us US citizens in your
desperation hoping to make us feel guilty when we give you already
$$$$ 5+ Billion dollars every year each year for the last 60 years
and all we get from you in return is war and mayhem because of you?
Zion Herbie, because of your loudmouthed hatred, fanaticism,
megalomania, self-anointment and self-aggrandizing, you Herbie
don't wanna hear the naked truth and you have become too blind
to see and notice how subtle and widespread Anti-Semitism has
become in the US. To wit as of late: Mel Gibson, Jodie Foster,
Patrick Swayze and other Hollywood folks... and even Fox's O'Reilly
exudes frequent Freudian slips letting his disdain shine thru for
loud Jews like you and your Zionist ilk... and Sen. Joe Lieberman, a
Jew, just lost his re-election in today's 2006 primary... and Joe was
probable cause as VP-nominee to have cost Al Gore the presidency
to Bush in the 2000 election. Another "victim" who lost the election
for president due to his Jewish origins may have been John Kerry
(Kohn)
Can't you see the hand-writing on the wall, Herbie, you olde kacker?
... All your cursing and cussing me and all your whining and phony
goodie-2-shoeing you did at the top of this post ain't gonna change
an iota in the EXISTING facts ... Still, you don't wanna hear it... ahahaha
Your B'nai Brith bitterly whined in 2005 that there were 300'000 fever
Jews in the year 2000, in the US, then there were in 1970. It was on
CNN for a whole week. These 300'000 were the smart and decent
Jews. You are not one of them.... obviously.... ahahahaha...
BTW, olde kacker, why do you call me "hateful" when I simple recite
and point out publicly known facts that may be at least beneficial if not
existential for you?... Are you that far off center and focus, Herbie?....
Never the less, Hebie, Thanks for the laughs..... ahahaha....
ahahaha.... ahahanson
**Caveat**: If you, Zion-Herbi, can show me that the establishment
of Israel in 1948 was nothing but the start of a new, now 60 year old
crusade by the Christians and by the Anglo Goys against the
Muslims, and that both of them, the Xians and the A-goys have
used and are USING you Jews for THEIR purposes, and you can
demonstrate to me that you Jews (collectively) have not fucked up
their efforts with your Jewish self-interests then we have an entirely
different story at hand...
If so, then I may re-evaluate my views.... ahahaha..