Linked Questions

65
votes
16answers
16k views

Why does kinetic energy increase quadratically, not linearly, with speed?

As Wikipedia says: [...] the kinetic energy of a non-rotating object of mass $m$ traveling at a speed $v$ is $mv^2/2$. Why does this not increase linearly with speed? Why does it take so much ...
21
votes
8answers
8k views

Since cables carry electricity moving at the speed of light, why aren't computer networks much faster?

Why can't cables used for computer networking transfer data really fast, say at the speed of light? I ask this because electricity travels at the speed of light. Take Ethernet cables for example, I ...
11
votes
6answers
10k views

How efficient is an electric heater?

How efficient is an electric heater? My guess: greater than 95%. Possibly even 99%. I say this because most energy is converted into heat; some is converted into light and kinetic energy, and ...
12
votes
11answers
810 views

What objective criteria distinguish between valid science, fringe science and pseudoscience in physics?

Plenty of research activity in physics have been vigorously opposed by their opponents as pseudoscience or fringe science, while other research are mainstream. It is possible some topic is ...
4
votes
5answers
563 views

This sentence makes no sense, electrostatics and electrons moving in a conductor - current

I highlighted the part where the confusion is. The sentence said that the potential difference is 0, yet it then immediately talks about how electrons can have motion. What are they trying to ...
13
votes
2answers
2k views

Is kinetic energy a relative quantity? Will it make inconsistent equations when applying it to the conservation of energy equations?

If the velocity is a relative quantity, will it make inconsistent equations when applying it to the conservation of energy equations? For example: In the train moving at $V$ relative to ground, ...
1
vote
5answers
973 views

What experiments prove the greenhouse effect?

What experiments prove the greenhouse effect? I've read a little on wikipedia but I've got only some names but not their experiments.
2
votes
2answers
1k views

Appearance of atoms

I was watching a documentary entitled "The Atom" and one of the statements made was that Atoms behave differently when we look at them. I wasn't too sure about the reasoning behind this and i'm hoping ...
0
votes
1answer
704 views

Famous physicists' quotations [closed]

I recently watched Sydney Coleman's 'Quantum Mechanics In Your Face,' and very much enjoyed it. (Highly recommended.) In it, Professor Coleman quotes a very clever comment by a philosopher called ...
2
votes
0answers
193 views

false false beliefs in physics [closed]

Reading Common false beliefs in Physics I feel that there are also "fake false beliefs", ie, that the "false belief" does not actually exists, it is a rhetorical argument or just a basis for ...
2
votes
0answers
143 views

What near-future measurement technique improvements will extend our physical knowledge?

Inspired by the wiki-article on atom-lasers: Another application, which might also benefit from atom lasers, is atom interferometry. In an atom interferometer an atomic wave packet is ...