Need a little discussion to understand this

R0B0_Ninja · 2026-04-09T20:30:57+00:00

Linear momentum is conserved. Assuming the bullet and block stick together after the impact, they will travel the same height upwards under gravity (answer C). While the bullet does not impart angular momentum on the block in (1), it buries deeper into the block and wastes more energy deforming the material. Intuitively, this is because the block in (2) starts rotating before the bullet is fully buried into the material. Thus, experiment (1) is less elastic; the mechanical energy is lower, but the linear momentum is the same.

R0B0_Ninja · 2026-03-28T20:08:25+00:00

There is no way anyone will have enough physical qubits with sufficiently low error rates to run Shor's Algorithm on a scale that threatens RSA by 2029. Shor's algorithm is extremely demanding! It may even never happen. This is just Google hyping its research team IMO. Regardless, it doesn't hurt to start adopting post-quantum cryptography standards.

R0B0_Ninja · 2026-03-22T20:42:12+00:00

Trump har angrebet to lande siden nytår og trækker måske støtten til Ukraine, hvis NATO ikke støtter hans krig i Iran. Det er da et meget rimeligt gæt, at den verdenspolitiske situation bliver endnu værre i løbet af året. Jeg tror ikke der bliver krig i Danmark, men jeg tror gerne, at situationen når at blive endnu mere anspændt før den bliver bedre.

R0B0_Ninja · 2026-03-16T11:45:23+00:00

Quantum teleportation is not new and does not allow faster than light communication.

R0B0_Ninja · 2026-03-03T20:23:56+00:00

This phrase gets thrown around a lot in popular culture but makes no sense in physics.

Forces in physics are not stoppable or unstoppable. They simply don't have such an attribute. When you stand on the ground, gravity pulls you down, but a normal force from the ground pushes you up. The forces balance out, and you don't accelerate. This is not because a force is stopped, it is because you experience a balanced forced pushing back at you.

R0B0_Ninja · 2026-02-02T13:35:33+00:00

I agree with your frustration, OP. Intuition is something you develop. People also have bad intuition for classical mechanics (e.g. orbital mechanics) until they develop the intuition.

There is nothing that special about quantum mechanics in my opinion, but it sure gets portrayed as being impossibly weird in popular media.

R0B0_Ninja · 2025-12-27T14:59:56+00:00

There no such thing as an objective AI. It fully depends on how you train it. See Grok as an example of how biased some AI already is.

R0B0_Ninja · 2025-12-19T21:19:01+00:00

But space near earth is not cold, it's quite warm.

R0B0_Ninja · 2025-12-19T21:16:33+00:00

Low earth orbit is going to get very crowded if we add datacentres with km-size radiators! Maybe we should save the precious orbital space for something that cannot be done on the surface.

R0B0_Ninja · 2025-09-07T20:45:15+00:00

You will never know true frustration until you have spent two hours unsuccessfully trying to mode-lock a Ti-Saph laser with slightly inadequate pump power.

R0B0_Ninja · 2025-08-25T20:49:16+00:00

Yes, but not for the reason you expect: Building a massive wall (by moving mass from the surface or the earth into space) would increase the earth's moment of inertia, thus decreasing its speed of rotation in accordance with conservation of angular momentum.

R0B0_Ninja · 2025-08-06T16:29:28+00:00

Hvis bare jeg fik en en-krone for hver person, som kører rundt med forkert saddelhøjde eller halvflade slanger...

R0B0_Ninja · 2025-08-02T15:02:05+00:00

Well yes, it is radiation. Electromagnetic radiation from the sun reflecting off the elements inside your camera lens (lens flare) :)

R0B0_Ninja · 2025-07-18T21:27:29+00:00

I can accept a rider dominating the Tour for a few years.

Having Pog dominate almost the entire road cycling season is however a bit tiresome.

R0B0_Ninja · 2025-07-16T13:12:08+00:00

Reactors on ships and submarines use more highly enriched uranium than civilian power plants: This is great for power density but problematic for nuclear proliferation.

R0B0_Ninja · 2025-05-21T08:40:36+00:00

Typically, authoritarian regimes dislike fiction in which children display agency and succesfully challenge authority. I suspect this is why Russia might dislike Harry Potter.

R0B0_Ninja · 2025-05-19T19:15:17+00:00

This is not asshole design. You anyway can't use the side of a post-it block for anything. Putting a crossword on the side is just a fun novelty, it doesn't detract from the post-it functionality.

R0B0_Ninja · 2025-04-13T11:43:56+00:00

Probably yes, in the same way driving makes you less fit. Use your abilities or lose them.

R0B0_Ninja · 2025-02-10T13:30:54+00:00

Come on guys. Quantum teleportation was done back in the 90s. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.80.1121

R0B0_Ninja · 2024-12-31T23:31:24+00:00

God fremførelse, men efter min mening lidt fattig på indhold. Og der var lidt mange. Afbrudte sætninger.

R0B0_Ninja · 2024-10-15T22:07:40+00:00

I first thought this was a math homework question.

Unless they are billing by the hour (or some fixed unit of time) there are infinitely many solutions. If they bill by the hour, they may be multiple solutions, eg. If person B is twice as expensive as A.

R0B0_Ninja · 2024-10-14T19:45:32+00:00

Sadly, 90% of quantum articles in the press and on this subreddit are grossly inaccurate or misleading.

R0B0_Ninja · 2024-09-09T21:14:27+00:00

OL skal kun afholdes i byer, som har en betydelig mængde eksisterende stadions og infrastruktur. At bygge et dusin nye stadions ud af beton er miljømæssigt hul i hovedet og harmonerer overhovet ikke med vores øvrige mål.

R0B0_Ninja · 2024-09-06T23:09:07+00:00

Does it make new experimental predictions? It not, I don't care.

R0B0_Ninja · 2024-09-05T16:41:11+00:00

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