Julius Sumner Miller Lesson 2: Newton's First Law of Motion - Inertia

00:14:45
https://www.youtube.com/watch?v=Kx2yqEB20k8

Zusammenfassung

TLDRLa vidéo, présentée par Julius Sumner Miller, explore le concept de l'inertie à travers des démonstrations pratiques illustrant les lois du mouvement de Newton. Elle commence par expliquer que l'inertie d'un objet est proportionnelle à sa masse et que c'est la tendance d'un objet à rester au repos ou en mouvement à moins qu'une force externe ne soit appliquée. Plusieurs expériences sont réalisées, comme frapper un bloc de bois sans le faire bouger, démontrer les effets de l'inertie sur une bille et une ficelle, et l'impact de la pression atmosphérique sur un morceau de papier. Miller démontre également par des expériences visuelles comment la force peut provoquer la rupture de cordes en tension sous différentes charges. En conclusion, il relie ces principes à des applications pratiques et fait référence à Isaac Newton, soulignant l'importance historique de ses découvertes.

Mitbringsel

  • 📌 L'inertie est la tendance naturelle des objets à résister aux changements de mouvement.
  • ⚖️ L'inertie est proportionnelle à la masse d'un objet.
  • 🧱 L'inertie peut être démontrée à travers des expériences simples comme frapper un bloc de bois.
  • 🎈 La force centripète montre que les objets se déplacent dans une trajectoire tangentielle lorsqu'ils sont relâchés.
  • 🪢 Les démonstrations incluent la rupture de cordes en fonction de la tension appliquée.
  • 🌬️ Les effets de la pression atmosphérique peuvent être illustrés avec une feuille de papier.
  • 🚗 Lors d'une accélération soudaine, la tête se penche en arrière.
  • 🔩 Une brique peut être frappée sans douleur due à son inertie.
  • ⚙️ Les expériences montrent la simplicité et la force des lois de Newton.
  • 📚 Isaac Newton a considérablement contribué à notre compréhension des lois physiques.

Zeitleiste

  • 00:00:00 - 00:05:00

    Dans cette vidéo, Julius Sumner Miller présente le concept d'inertie et comment il est lié à la masse. Il commence par expliquer que l'inertie est la tendance d'un objet à résister à un changement de mouvement. Un bloc de bois sur une table illustre cette notion en voulant rester au repos. Miller démonte ensuite que doubler la masse d'un objet double également son inertie, en montrant que l'inertie est synonyme de masse, conformément à la première loi de Newton. Il poursuit avec une démonstration pratique avec deux paquets pour prouver que plus un objet a de masse, plus il a d'inertie. Miller illustre également les deux volets de la première loi de Newton à l'aide d'une tige insérée dans un bloc de bois : lorsqu'un coup est donné, le bloc reste au repos tandis que la tige s'enfonce, démontrant qu'un objet au repos veut rester au repos.

  • 00:05:00 - 00:14:45

    Miller stipule ensuite que la même première loi est visible avec des forces appliquées à des cordes supportant des poids différents. En tirant rapidement ou lentement sur la corde inférieure, il choisit laquelle se brisera, démontrant que la force d'inertie résiste différemment à une tension rapide ou progressive. En guise de démonstration dramatique de l'inertie, il présente un exemple classique avec une feuille de papier frappée qui reste immobile en raison de la pression atmosphérique la retenant en place. Les diverses expériences, allant du renversement d'une voiture en mouvement au défi de déplacer un poids à travers une impulsion soudaine, mettent en lumière la puissance de l'inertie comme l'enseignait Newton. Enfin, Miller montre comment l'inertie permet de réaliser des expériences pratiques comme avec des tasses supportant un poids grâce à leur résistance inertielle. Il termine en rendant hommage à Isaac Newton, soulignant l'importance capitale de ses contributions à la science des mouvements et forces naturelles.

Mind Map

Mind Map

Häufig gestellte Fragen

  • Qui a présenté la vidéo ?

    La vidéo a été présentée par Julius Sumner Miller.

  • Quel est le sujet principal de la vidéo ?

    Le sujet principal de la vidéo est l'inertie et les lois du mouvement de Newton.

  • Comment est démontrée l'inertie avec les blocs de bois ?

    L'inertie est démontrée en montrant que les blocs de bois ont tendance à rester au repos ou en mouvement jusqu'à ce qu'une force externe intervienne.

  • Quel exemple est utilisé pour expliquer la force centripète ?

    Une boule attachée à une ficelle est utilisée pour expliquer la force centripète, montrant que la boule se déplace tangentiellement lorsqu'elle est relâchée.

  • Qu'est-ce qui cause une corde à se casser dans l'expérience avec les poids ?

    Selon la force et la rapidité de la traction, la corde supérieure ou inférieure se casse en démontrant l'inertie du poids.

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Untertitel
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Automatisches Blättern:
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    [Music]
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    how do you do ladies and gentlemen I am
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    Julius sna Miller and physics is my
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    business and I should say how do you do
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    ladies and gentlemen and boys and girls
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    I am Julia sna Miller and physics is my
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    business and I'll special business today
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    is the subject of inertia and I must
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    make the matter the idea clear as
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    follows here we have a block of wood at
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    rest on the tabletop and I ask what does
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    that block want to do answer the block
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    wishes to remain at rest supposing now I
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    have double as much block and I try in
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    turn to put that system in motion what
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    do I discover it also wishes to remain
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    at rest moreover it wishes to remain at
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    rest twice as much and therefore we say
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    its inertia is twice as great and so you
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    discover at once that I have used the
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    term inertia and referred to the idea of
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    mass as synonymous so mass and inertia
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    are synonymous and this is all tied up
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    beautifully in Newton's first law which
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    says what if a body is at rest it wishes
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    to remain at rest and if it is moving
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    uniformly in a straight line that's what
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    it wants to do in English simply
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    whatever a body is doing that's what it
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    wants to do let's look at Newton's Latin
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    for it Newton put it in Latin axata sewa
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    legus motus axioms even laws Laws of
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    Motion Corpus Omni persa inst to suo
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    quendi and so on and in English a little
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    more within our compet
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    everybody continues in its state of rest
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    or of uniform motion in a straight line
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    unless there are some forces to divert
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    it consider now the
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    following here you come on April Fool's
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    Day let us say on a package on two
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    packages resting on the ground here is
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    one and here is another and you deliver
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    you impose a force on the one I will
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    instead of with my foot with my hand and
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    it experienced such a motion the force
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    produced a motion in the body of so much
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    inertia now I try it with this
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    one hardly as much motion why this one
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    is filled with rags and this one with
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    two bricks and this one has the greater
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    inertia so the measure of the mass of a
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    body is its inertia consider now the two
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    aspects of Newton's first law
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    a body at rest wishes to remain so here
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    I have a heavy block of wood a hole in
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    it and I put a dow rod in the hole the
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    Dow Rod constitutes the
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    handle how can I put that handle into
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    the block as follows as follows notice
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    what happens I hit the handle the block
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    remains at rest whereupon the handle
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    moves into the block that's the first
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    law the body of large inertia wishes to
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    remain at rest let me pursue this in
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    another way to demonstrate the second
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    part of Newton's law what did the second
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    part
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    say if the body is in uniform motion in
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    a straight line that's what it wants to
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    do I start
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    again now I come down on a firm block
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    the motion of the handle is
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    arrested the handle and the block were
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    moving and what does the block want to
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    do keep moving
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    whereupon it lodges itself more firmly
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    on the handle thus do we demonstrate
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    Newton's first law in two
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    parts let me do this another way very
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    pretty very pretty I have a
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    support and a weight w supported by a
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    string and another string with a loop in
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    it here which I shall show you let me
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    call this string a and this string
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    B I propose to do as
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    follows I'm going to pull on string B
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    the lower
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    string and I can break either string b
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    or string a by invoking Newton's first
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    law if I pull suddenly on string b w
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    wishes to remain at rest and B will
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    break on the other hand if I pull gently
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    on B A supports W already there plus the
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    force I impose and I shall show you that
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    exactly with this
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    demonstration here is a
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    string here is a hook here is a weight
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    and the upper string is supporting the
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    load here is the lower string and I am
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    putting a little Rod inside here so that
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    my hand is Not underneath should the
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    weight fall I am going to break the
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    lower string watch it now the lower one
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    there it is I broke it now I am going to
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    change the
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    string I'm going to change the
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    string and now I'm going to break the
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    upper string by pulling slowly on the
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    lower one watch it now watch we hope
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    that breaks now supposing it does
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    not one is led to say the experiment has
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    failed and I say no the experiment
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    doesn't fail fail I have failed to meet
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    the requirements of nature watch I'm
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    going to break the upper string there it
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    is and so we can be applauded for
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    Success consider another demonstration
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    of the same here is an enormous weight
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    16bs here is a string attached to
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    it if I pull on that string in a gentle
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    way I'll do it by hand in a gentle way
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    uhuh the Str can support the load now
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    let me try to accelerate it what does
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    Newton's first law say body wants to
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    remain at rest it has enormous inertia
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    watch it do you see the string has
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    broken I shall have more to say about
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    this when I talk about Newton Second Law
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    the second law consider now another
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    dramatic
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    demonstration an application of Newton's
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    first law because we must not escape the
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    fact that these laws of physics of
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    nature of science have vast applications
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    in plean things a brick a Trel can not
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    the Craftsman the brick layer utilize
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    Newton's first law in this way notice if
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    he hit his hand with the TR he'd hurt it
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    but he can hit the Breck with absolute
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    abandon and feel nothing inertia of the
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    break here is another classic which I
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    like to know because it it is so
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    dramatic a sheet of
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    paper about 20 in by 30 20 in by 30 600
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    square in the load on each square inch
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    is roughly 15 PB atmospheric pressure at
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    sea level therefore about 9,000 lbs of
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    air on that paper that's enormous
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    inertia proof here is a board quarter
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    inch thick I put the board under here
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    and now I am going to try to put that
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    enormous mass of air into motion by a
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    sudden impulsive blow on this end of the
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    stick the impulsive view that people
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    have is oh the whole thing will catapult
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    no it will not because that mass of air
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    is at rest and Newton said it wishes to
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    remain so watch
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    it it did not
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    move it did not move
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    fantastic now
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    remember ladies and gentlemen and boys
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    and girls when I refer to this block
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    being at rest and then I say what does
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    it want to do and the answer is it wants
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    to remain at rest I would not have you
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    dispose of this as trivia because it
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    took the genius of an Isaac Newton to
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    establish it nothing trivial about it
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    consider another dramatic demonstration
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    oh this one is a here is a vessel of
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    water and it has quite some inertia and
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    I put it on these this paper and I move
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    it slowly
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    slowly remember this has large inertia
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    it wants to remain at rest and I am not
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    trying to accelerate it to rapidly and
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    thereby friction forces hold it onto the
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    paper and so I pull more and more and
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    more and more uhoh we're in a little
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    trouble because friction isn't right for
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    me but anyone in his right mind must
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    testify to the prospect if I continue in
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    the manner I have been doing the whole
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    thing will fall down but if I invoke the
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    laws of Newton the first law which says
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    it wants to remain at rest and will
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    refuse to be moved by short lived
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    impulsive forces watch
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    it are you not surprised that it stayed
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    there
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    consider another more
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    application here is a vehicle and here
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    is a body standing upright in the
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    vehicle and now I want to show you that
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    if I move the vehicle the body is at
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    rest with respect to it and what does it
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    want to do it wants to stay there watch
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    it and so it did and that's why when you
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    accelerate a car rapidly from a
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    standstill your head is jerked back
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    because of the large inertia of the head
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    on the other hand if the car is moving
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    moving
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    uniformly if I now suddenly arrest its
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    motion what will the block do well the
  • 00:10:35
    block was going straight and that's what
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    it wants to do oh notice I accelerated
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    too fast the first
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    way there it is and the block tip
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    forward a quick one for your inquiry
  • 00:10:49
    here I have two vessels and remember the
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    subject is
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    inertia they each contain one pint and
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    let us say that one is filled with cream
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    and the other with milk so I have a pint
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    of milk and a pint of cream quickly
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    quickly which has the greater inertia
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    that's equivalent to asking which has
  • 00:11:09
    the greater mass that's equivalent to
  • 00:11:12
    asking which has the greater weight and
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    some are led to say oh the cream the
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    cream of course because it's thick and
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    sluggish and viscous oh no no no mistake
  • 00:11:23
    the milk has the greater inertia for
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    reasons of course you see clearly
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    yourself the Pine of milk weighs more
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    than the pint of cream another
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    demonstration of the inertia again here
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    is a stack of coins they happen to be
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    Australian pennies why because they have
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    larger inertia than us pennies and now
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    what can I do with a thin blade I can
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    deliver a sharp impulsive blow to the
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    lowermost one and what do I hope to see
  • 00:11:53
    I hope to see the whole stack remain
  • 00:11:56
    unmoved why because it it's at rest and
  • 00:11:58
    wants to stay say there it is there it
  • 00:12:01
    is there it is and I just love that
  • 00:12:04
    demonstration why because it is a
  • 00:12:07
    classic revealing the beauty and
  • 00:12:09
    strength and simplicity in a sense of
  • 00:12:12
    Newton's first
  • 00:12:15
    law I want to show one
  • 00:12:18
    more remember what the second part of
  • 00:12:20
    the law said I would urge you never to
  • 00:12:23
    forget that the first law has two parts
  • 00:12:26
    which are rarely ever properly separated
  • 00:12:29
    I said a body moving in a straight
  • 00:12:31
    line wishes to continue so here is a
  • 00:12:34
    ball swinging in a vertical plane in a
  • 00:12:37
    vertical Circle I would remind you I
  • 00:12:40
    would remind you that at the instant in
  • 00:12:43
    question when the ball is right there on
  • 00:12:46
    the end of the string its motion is
  • 00:12:48
    tangent to the path at that place and if
  • 00:12:50
    I should cut the string or let go of it
  • 00:12:53
    the ball would not go radially outward
  • 00:12:55
    but would go instantaneously in a
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    direction tangent
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    so this introduces here in a passing way
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    the idea of centrifugal force which is a
  • 00:13:08
    nasty thing to handle and often much is
  • 00:13:11
    said that is wrong but if I let go of
  • 00:13:13
    the string at the top where will the
  • 00:13:16
    ball go tangent watch
  • 00:13:19
    it there it is tangent now it is proper
  • 00:13:23
    before we conclude a program on Isaac
  • 00:13:25
    Newton to show you one of many
  • 00:13:30
    photographs of
  • 00:13:34
    Newton a very important place this man
  • 00:13:37
    occupies in the history of
  • 00:13:40
    humankind and I would hope that when you
  • 00:13:43
    go to London sometime you will most
  • 00:13:45
    certainly go to Westminster Abbey and
  • 00:13:48
    see where he is buried and what does it
  • 00:13:50
    say on that beautiful Epitaph among
  • 00:13:53
    other
  • 00:13:55
    things let men Rejoice that so great a
  • 00:13:58
    one
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    has
  • 00:14:01
    existed so we are coming shortly to the
  • 00:14:03
    end of the program one final enchanting
  • 00:14:07
    thing an array of cups if I put this
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    heavy block on them
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    gently I can drive this Spike into that
  • 00:14:17
    block without the cups feeling anything
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    why why because the black the block has
  • 00:14:24
    enormous inertia if on the other hand I
  • 00:14:26
    drop it it's going and it want to keep
  • 00:14:29
    going there it is and thus I conclude
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    ladies and gentlemen a program on
  • 00:14:35
    inertia and I thank you for your
  • 00:14:37
    attention
  • 00:14:40
    [Music]
Tags
  • inertie
  • Newton
  • lois du mouvement
  • physique
  • démonstration
  • masse
  • force
  • expériences
  • Julius Sumner Miller
  • éducation