meta user
network profile
| bio | website | |
|---|---|---|
| location | ||
| age | ||
| visits | member for | 2 years, 6 months |
| seen | Mar 11 at 12:15 | |
| stats | profile views | 21 |
|
Jan 27 |
comment |
Is it possible for a physical object to have a irrational length? The problem I see with your question is that you have defined a hypothetical caliper and are complaining when people are applying it to hypothetical objects. You can only measure physical objects with physical calipers, and hypothetical objects with hypothetical calipers. |
|
Nov 18 |
awarded | Commentator |
|
Nov 18 |
comment |
I'm having trouble understanding the dimensions of this falling body problem Anyway, yes, the $5$ has dimensions of force per unit velocity = $\mathrm{N\:s\:m^{-1} = kg\:s^{-1}}$. This is no more unusual than if I were to say a thermometer's mercury level rises 2 millimeters whenever the temperature goes up by a degree Celsius, giving units of $\mathrm{m\:K^{-1}}$. |
|
Oct 29 |
awarded | Editor |
|
Oct 29 |
revised |
What does the wind speed have to be to blow away a person? fixed links |
|
Oct 29 |
suggested | suggested edit on What does the wind speed have to be to blow away a person? |
|
Jul 24 |
comment |
Can one make a ball rotate around a vertical axis using only a combination of horizontal axis rotations? What is the exact text of the problem? |
|
Jul 24 |
comment |
Can one make a ball rotate around a vertical axis using only a combination of horizontal axis rotations? What is the model of "pushing" here? I would assume it means applying an impulse to instantaneously change the angular velocity, $\omega_\text{after} = \omega_\text{before} + \Delta \omega$, but then the answer is a trivial "no". |
|
Jul 24 |
comment |
Can one make a ball rotate around a vertical axis using only a combination of horizontal axis rotations? By the way, this is known as a kugel ball. Question: by "turn around the vertical axis" do you mean produce a net rotation or impart an angular velocity about the vertical axis? |
|
Jun 10 |
awarded | Teacher |
|
Jun 10 |
answered | How fast do you need to travel to go 35 light-years in 2 (apparent) years? |
|
Jun 10 |
comment |
How fast do you need to travel to go 35 light-years in 2 (apparent) years? Actually, your first formula is backwards. The proper time experienced by an observer moving with speed $v$ for time $T$ is $t' = t\sqrt{1 - v^2/c^2}$. Otherwise, you would experience more time the faster you go, in contradiction to the twin paradox. |
|
Jun 3 |
comment |
Apparent contradiction between calculations and intuition? Consider that the wave speed on the other side of the barrier is infinite. In that respect, your scenario is like a sound wave hitting an infinitely stiff object: no displacement is possible, and the wave returns inverted in phase. (Also worth noting is that $\lvert R \rvert$ is zero only when the potential difference is zero, i.e. there is no boundary at all!) |
|
Mar 25 |
comment |
Is acceleration relative? This is more a question for physics.SE, but the short answer is that acceleration is not relative when measured in an inertial frame of reference. |
|
Sep 28 |
comment |
Physics tension question Yes, that's correct. Another way to see this is that it takes 180 N to accelerate the 60 kg body at 3 m/s², and the only place that force can come from is the tension in the cord. |
|
Nov 11 |
awarded | Supporter |
