Timeline for The Meaning of Newton's Second Law of Motion Being Invariant Under Certain Transformations
Current License: CC BY-SA 3.0
13 events
| when toggle format | what | by | license | comment | |
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| Oct 10, 2018 at 23:11 | comment | added | JEB | why is there an x-axis? Isn't this a 1 dimensional problem? Why are the frames accelerating? why are there 3 frames. Why is $v'$ in $S''$ and $u$ in $S'$? A big part of making physics make sense is focusing on what matters, knowing what to ignore, and definitely naming variables sensibly. | |
| Feb 17, 2017 at 23:11 | comment | added | Samama Fahim | By F = ma being valid in both frames, we mean the value of the force in both frames is the same? Is it because we somehow know that the force is not changing but getting different values for it indicates that there is something wrong? | |
| Feb 17, 2017 at 23:02 | comment | added | ZeroTheHero | Correct. For instance the velocities in different frames would be different, and the distances travelled would also be different. The physical law $F=ma$ would be valid in both. | |
| Feb 17, 2017 at 23:00 | comment | added | Samama Fahim | What do you make of this statement from my textbook: 'Different observers in different inertial frames may have different values of physical quantities but the basic physical laws (Relationships between the measured physical quantities) will always remain the same for all observers.'? | |
| Feb 17, 2017 at 22:50 | comment | added | ZeroTheHero | The forces in the two frames would not be the same, i.e. $F'\ne F$. $F=ma$ is an operational definition of force so if $a'\ne a$ then $F'\ne F$. That's invariance: i.e. numerical values do not change. | |
| Feb 17, 2017 at 22:46 | comment | added | Samama Fahim | If they are not inertial, the relationship between force and acceleration 'a' as measured in a non-inertial frame is not F = ma? | |
| Feb 17, 2017 at 22:41 | comment | added | Samama Fahim | How do you show that the 'form' of the equation, whatever they mean by it, changes when you transform from an inertial frame to a non-inertial frame? | |
| Feb 17, 2017 at 22:41 | comment | added | ZeroTheHero | Yes. Up to rotations of the axes, the force and acceration will have the same numerical value in two inertial frames. If they are not inertial, anything goes and Newton's 3rd law will not yield the same numerical values for the forces and accelerations. | |
| Feb 17, 2017 at 22:39 | history | edited | ZeroTheHero | CC BY-SA 3.0 |
added 120 characters in body
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| Feb 17, 2017 at 22:39 | comment | added | Samama Fahim | What do you mean 'invariant'? The equations give the same value of a quantity? | |
| Feb 17, 2017 at 22:36 | history | edited | ZeroTheHero | CC BY-SA 3.0 |
added 120 characters in body
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| Feb 17, 2017 at 22:35 | comment | added | Samama Fahim | $\frac{du}{dt}$ is the acceleration of $S'$ as measured in $S$. $S'$ and $S''$ are non-inertial frames. | |
| Feb 17, 2017 at 22:32 | history | answered | ZeroTheHero | CC BY-SA 3.0 |