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Why does a spinning object speed up as it shrinks? This Hoberman sphere demonstration illustrates the law of conservation of angular momentum. Moment of inertia measures how mass is distributed relative to the axis of rotation. When the sphere collapses, its mass moves inward. This decrease in inertia forces... show more

The Scientific Lens

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16,700 次观看 • 3 个月前 •via X (Twitter)

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Prandtl Rotations describe the motion of a gyroscope's rotor around its principal axes. A gyroscope's main behavior is governed by the principles of angular momentum conservation, causing it to resist changes to its orientation. For a rotating gyroscope, stability along its axes is critical. Depending on the external influences (like additional weights, torques, or friction), these rotations can either remain stable (maintaining a steady motion) or become unstable, leading to wobbling or tumbling motions. When rotating about one of its principal axes (with the highest or lowest moment of inertia), the gyroscope exhibits stable behavior. If additional forces or masses alter its inertia, the gyroscope may cross a critical stability threshold, leading to unstable rotations. [1] .

Prandtl Rotations describe the motion of a gyroscope's rotor around its principal axes. A gyroscope's main behavior is governed by the principles of angular momentum conservation, causing it to resist changes to its orientation. For a rotating gyroscope, stability along its axes is critical. Depending on the external influences (like additional weights, torques, or friction), these rotations can either remain stable (maintaining a steady motion) or become unstable, leading to wobbling or tumbling motions. When rotating about one of its principal axes (with the highest or lowest moment of inertia), the gyroscope exhibits stable behavior. If additional forces or masses alter its inertia, the gyroscope may cross a critical stability threshold, leading to unstable rotations. [1] .

Craig Stone

464,952 次观看 • 1 年前

«Physics works» Provided the initial speed of the weight is zero, the conservation of momentum will allow the ball to touch the girl's face, and not crush it. 0th Newton's law: don't move. [📹 spider_slack]

«Physics works» Provided the initial speed of the weight is zero, the conservation of momentum will allow the ball to touch the girl's face, and not crush it. 0th Newton's law: don't move. [📹 spider_slack]

Massimo

4,927,848 次观看 • 2 年前

A cheetah hitting a sharp turn at high speed should logically skid out, but it doesn't. The secret is the tail. This muscular rudder acts as a high-speed stabilizer. By whipping it in the opposite direction of a turn, the cheetah creates counter-torque to balance its center of mass. This allows for rapid pivots while semi-retractable claws provide permanent, spike boots-like traction. It’s pure biomechanics using physics to manage angular momentum. While we build supercars with active spoilers, nature perfected this steering millions of years ago. VC: Lemurt Wildlife #wildlife #nature #predator #cheetah #biomechanics

A cheetah hitting a sharp turn at high speed should logically skid out, but it doesn't. The secret is the tail. This muscular rudder acts as a high-speed stabilizer. By whipping it in the opposite direction of a turn, the cheetah creates counter-torque to balance its center of mass. This allows for rapid pivots while semi-retractable claws provide permanent, spike boots-like traction. It’s pure biomechanics using physics to manage angular momentum. While we build supercars with active spoilers, nature perfected this steering millions of years ago. VC: Lemurt Wildlife #wildlife #nature #predator #cheetah #biomechanics

Dr. PM Dhakate

58,609 次观看 • 3 个月前

Good example of how getting stronger isn't just about adding quality mass to generate more momentum. The strength to decelerate proximal segments (pelvis rotation, trunk flexion, trunk rotation), allows for improved energy/momentum transfer into the arm. Here's a visual I've used before that applies to Misiorowski's HS > Pro transformation. When the pelvis doesn't stick, the trunk can't fully accelerate. When the trunk doesn't stick, the arm can't fully accelerate. Lower body strength/mass improves velocity through the mass component of the physics equation, but it also provides the ability to effectively decelerate so you can "crack the whip," send energy proximal to distal and create insane arm speeds.

Good example of how getting stronger isn't just about adding quality mass to generate more momentum. The strength to decelerate proximal segments (pelvis rotation, trunk flexion, trunk rotation), allows for improved energy/momentum transfer into the arm. Here's a visual I've used before that applies to Misiorowski's HS > Pro transformation. When the pelvis doesn't stick, the trunk can't fully accelerate. When the trunk doesn't stick, the arm can't fully accelerate. Lower body strength/mass improves velocity through the mass component of the physics equation, but it also provides the ability to effectively decelerate so you can "crack the whip," send energy proximal to distal and create insane arm speeds.

Ben Brewster

101,817 次观看 • 2 个月前

Astronaut Tim Peake demonstrates aboard the International Space Station, a stationary object in microgravity will tumble aimlessly with even the slightest tap. But once a gyroscope begins to spin, it instantly locks into a rigid geometric plane, stubbornly refusing to be tilted. This phenomenon is driven by angular momentum. The rapid rotation creates a powerful resistance to outside forces, granting the object an invisible, unyielding stability. This is far more than a simple physics trick. This exact principle of spin stabilization is what keeps the massive space station perfectly oriented as it orbits the Earth; a profound reminder that in the chaotic vacuum of space, sometimes the only way to stay perfectly still is to keep moving.

Astronaut Tim Peake demonstrates aboard the International Space Station, a stationary object in microgravity will tumble aimlessly with even the slightest tap. But once a gyroscope begins to spin, it instantly locks into a rigid geometric plane, stubbornly refusing to be tilted. This phenomenon is driven by angular momentum. The rapid rotation creates a powerful resistance to outside forces, granting the object an invisible, unyielding stability. This is far more than a simple physics trick. This exact principle of spin stabilization is what keeps the massive space station perfectly oriented as it orbits the Earth; a profound reminder that in the chaotic vacuum of space, sometimes the only way to stay perfectly still is to keep moving.

Cosmos Archive

507,693 次观看 • 3 个月前

"Moving forward while staying back" This makes zero sense at first glance, but is ultimately what needs to happen to generate maximum velocity. ✅We need the linear momentum of the stride. ✅We must find a way to convert as much of this into usable rotation (angular momentum) as possible. ✅We must do this on one leg. The most efficient throwers do this by spring-loading tension into the ground/back hip complex and holding that tension while building linear momentum down the slope.

"Moving forward while staying back" This makes zero sense at first glance, but is ultimately what needs to happen to generate maximum velocity. ✅We need the linear momentum of the stride. ✅We must find a way to convert as much of this into usable rotation (angular momentum) as possible. ✅We must do this on one leg. The most efficient throwers do this by spring-loading tension into the ground/back hip complex and holding that tension while building linear momentum down the slope.

Ben Brewster

11,144 次观看 • 7 个月前

NASA astronaut demonstrating the Dzhanibekov effect. An astronaut noticed this physical behavior of a handle, that turned out to be the proof of a theorem: the tennis racket theorem (also dubbed the Dzhanibekov effect) The Tennis Racket Theorem states that an object with three unique moments of inertia, rotation about the axis of intermediate moment of inertia is unstable, while rotation about the other two axis is stable. The effect is named after the Russian cosmonaut Vladimir Dzhanibekov who discovered this phenomenon while in space in 1985.

NASA astronaut demonstrating the Dzhanibekov effect. An astronaut noticed this physical behavior of a handle, that turned out to be the proof of a theorem: the tennis racket theorem (also dubbed the Dzhanibekov effect) The Tennis Racket Theorem states that an object with three unique moments of inertia, rotation about the axis of intermediate moment of inertia is unstable, while rotation about the other two axis is stable. The effect is named after the Russian cosmonaut Vladimir Dzhanibekov who discovered this phenomenon while in space in 1985.

Historic Vids

23,642,929 次观看 • 2 年前

Hip rotation is one of the primary drivers of velocity during the throw. Both speed and timing of rotation matter. The goal is to have the hips rotate out in front of the torso. Ideally, you want rotation to begin quickly after the front foot strikes the ground. The speed of rotation is also critical. I strive for all QBs that I work with to be 800+ deg/sec with hip rotation speed. One key thing is to not mistake “sliding” for rotating. Many will push and slide their hips forward as opposed to rotating against a stable lead leg.

Hip rotation is one of the primary drivers of velocity during the throw. Both speed and timing of rotation matter. The goal is to have the hips rotate out in front of the torso. Ideally, you want rotation to begin quickly after the front foot strikes the ground. The speed of rotation is also critical. I strive for all QBs that I work with to be 800+ deg/sec with hip rotation speed. One key thing is to not mistake “sliding” for rotating. Many will push and slide their hips forward as opposed to rotating against a stable lead leg.

Joe Mohr

12,648 次观看 • 2 个月前

It's easier to explain why the moon shouldn't exist than why it does. All theories of lunar origin don't make sense. The moon's mass and assumed density suggest it should have settled into spherical form... with a single center of mass. Free to rotate on any axis. But the moon's rotation is completely and precisely locked to its orbital period around Earth. This implies mass is not distributed radially symmetrical. A huge anomaly. Something within the lunar crust is extremely rigid.

It's easier to explain why the moon shouldn't exist than why it does. All theories of lunar origin don't make sense. The moon's mass and assumed density suggest it should have settled into spherical form... with a single center of mass. Free to rotate on any axis. But the moon's rotation is completely and precisely locked to its orbital period around Earth. This implies mass is not distributed radially symmetrical. A huge anomaly. Something within the lunar crust is extremely rigid.

Randall Carlson

29,758 次观看 • 6 个月前

🔩 An unexpected twist in space The Dzhanibekov effect: an object rotating in zero gravity suddenly flips its axis of rotation. This occurs due to differences in the moments of inertia across the three axes, causing rotational instability. Demonstrated by Vladimir Dzhanibekov in 1985, this phenomenon shows how even a simple nut behaves unpredictably in orbit. 🤔

🔩 An unexpected twist in space The Dzhanibekov effect: an object rotating in zero gravity suddenly flips its axis of rotation. This occurs due to differences in the moments of inertia across the three axes, causing rotational instability. Demonstrated by Vladimir Dzhanibekov in 1985, this phenomenon shows how even a simple nut behaves unpredictably in orbit. 🤔

Black Hole

40,870 次观看 • 21 天前

Physics feels stable, predictable, and well-behaved largely because we learned it in 3D. That comfort hides a trap. In 1907, Paul Ehrenfest pointed out something unsettling. If you take the laws we treat as fundamental and transplant them into a different number of spatial dimensions, they often stop working the way we expect. Not just numerically different but qualitatively different. The issue isn’t the force law by itself but it's geometry. Gauss’s law ties inverse-square forces to the surface area of spheres, and sphere geometry depends on dimension. Change the dimension, and the same-looking force produces a different potential, a different balance of attraction and inertia, and a different fate for motion.

Physics feels stable, predictable, and well-behaved largely because we learned it in 3D. That comfort hides a trap. In 1907, Paul Ehrenfest pointed out something unsettling. If you take the laws we treat as fundamental and transplant them into a different number of spatial dimensions, they often stop working the way we expect. Not just numerically different but qualitatively different. The issue isn’t the force law by itself but it's geometry. Gauss’s law ties inverse-square forces to the surface area of spheres, and sphere geometry depends on dimension. Change the dimension, and the same-looking force produces a different potential, a different balance of attraction and inertia, and a different fate for motion.

Mathelirium

30,521 次观看 • 3 个月前

This video is controversial but I’d like to explore its physics in this thread As I see it the potential energy of the nails convert to kinetic energy so it transfers energy all through the box the entropy of the system is increased 1/🧵

This video is controversial but I’d like to explore its physics in this thread As I see it the potential energy of the nails convert to kinetic energy so it transfers energy all through the box the entropy of the system is increased 1/🧵

Science girl

17,380,152 次观看 • 3 年前

String Theory is one of the few frameworks that tries to describe Quantum Physics and Gravity in the same mathematical language. In this animation, the glowing loop is the string, the shifting color along it represent its quantum vibration modes, and the surrounding fabric is a proxy for Spacetime responding. When you quantize a string, one of its vibration modes behaves like a graviton. So, geometry shows up as part of the same quantum system. #StringTheory #QuantumGravity #GeneralRelativity #QuantumPhysics #TheoreticalPhysics #PhysicsVisualization

String Theory is one of the few frameworks that tries to describe Quantum Physics and Gravity in the same mathematical language. In this animation, the glowing loop is the string, the shifting color along it represent its quantum vibration modes, and the surrounding fabric is a proxy for Spacetime responding. When you quantize a string, one of its vibration modes behaves like a graviton. So, geometry shows up as part of the same quantum system. #StringTheory #QuantumGravity #GeneralRelativity #QuantumPhysics #TheoreticalPhysics #PhysicsVisualization

Mathelirium

42,103 次观看 • 4 个月前

The fastest star in the Galaxy is S4714, which accelerates to approximately 24,000 km/s at its peak, or about 8% the speed of light. It orbits the supermassive black hole Sagittarius A* at the center of our Milky Way, moving in an extremely eccentric orbit. At its closest approach, it comes to a distance of approximately 1.8 billion km from the black hole—comparable to the distance from the Sun to Saturn. From this distance, the angular size of the "shadow" of Sagittarius A* is four times larger than the angular size of the Sun in Earth's sky! Observations of S4714, conducted with the European Southern Observatory, are helping to test the effects of general relativity in the extreme gravity of the Galactic center.

The fastest star in the Galaxy is S4714, which accelerates to approximately 24,000 km/s at its peak, or about 8% the speed of light. It orbits the supermassive black hole Sagittarius A* at the center of our Milky Way, moving in an extremely eccentric orbit. At its closest approach, it comes to a distance of approximately 1.8 billion km from the black hole—comparable to the distance from the Sun to Saturn. From this distance, the angular size of the "shadow" of Sagittarius A* is four times larger than the angular size of the Sun in Earth's sky! Observations of S4714, conducted with the European Southern Observatory, are helping to test the effects of general relativity in the extreme gravity of the Galactic center.

Black Hole

15,392 次观看 • 4 个月前

🧵 I watched the 1974 Land of the Lost when I was a kid, but I only understood the basics of it, on the surface it seemed like a silly children’s show. I had no understanding of the deep physics involved. This frankly blew me away. The scene in this thread explains the Law of Conservation of Mass in a closed system, Schrödinger’s Box theory, as well as Hawking Radiation and particles at the event horizon of a black hole, one set escaping, one being sacrificed.

🧵 I watched the 1974 Land of the Lost when I was a kid, but I only understood the basics of it, on the surface it seemed like a silly children’s show. I had no understanding of the deep physics involved. This frankly blew me away. The scene in this thread explains the Law of Conservation of Mass in a closed system, Schrödinger’s Box theory, as well as Hawking Radiation and particles at the event horizon of a black hole, one set escaping, one being sacrificed.

JenOakie42💫

326,459 次观看 • 1 年前

The moment when the House of Commons voted unanimously to call on the federal government to declare #MMIWG2S a Canada-wide emergency and implement a Red Dress Alert system. This government must speed up their delivery of resources and funding to stop this violence. #cdnpoli

The moment when the House of Commons voted unanimously to call on the federal government to declare #MMIWG2S a Canada-wide emergency and implement a Red Dress Alert system. This government must speed up their delivery of resources and funding to stop this violence. #cdnpoli

Leah ProudLakota (she/her)

115,335 次观看 • 3 年前

Here's the rotating movement of the stars on our flat Earth. It's an electromagnetic torus field with a plane of inertia in the middle. That's how the universe works! Believing that you live on a spinning globe traveling in space and chasing the sun, is their biggest mockery of your intelligence. I believe that one day this truth will be known and clear to all of humanity.

Here's the rotating movement of the stars on our flat Earth. It's an electromagnetic torus field with a plane of inertia in the middle. That's how the universe works! Believing that you live on a spinning globe traveling in space and chasing the sun, is their biggest mockery of your intelligence. I believe that one day this truth will be known and clear to all of humanity.

vegastar

300,095 次观看 • 2 年前

Every pilot needs to learn. Here is an approach with a 400m ULCS with a 2.3kts flood tide. The conning pilot is moving up in category to be able to pilot ULCS and is performing this maneuver under the supervision of 2 senior pilots. Conning pilot is not used to the mass and inertia of a ULCS, so underestimates the effect of the current running through and pushing him to the green side, almost swiping B85A with the stern. The maneuver is always under control, but the senior pilots advise the conning pilot to increase speed to avoid hitting B85a. As usual, there will be a debriefing and analysis of the maneuver. A good learning experience.

Every pilot needs to learn. Here is an approach with a 400m ULCS with a 2.3kts flood tide. The conning pilot is moving up in category to be able to pilot ULCS and is performing this maneuver under the supervision of 2 senior pilots. Conning pilot is not used to the mass and inertia of a ULCS, so underestimates the effect of the current running through and pushing him to the green side, almost swiping B85A with the stern. The maneuver is always under control, but the senior pilots advise the conning pilot to increase speed to avoid hitting B85a. As usual, there will be a debriefing and analysis of the maneuver. A good learning experience.

Bart 🌊⚓️

19,050 次观看 • 2 个月前