D&D 5E (2014) What rule(s) is 5e missing?

[James Gasik]

Thanks a lot, I rather like those rules, though I'd be tempted to add rules for spiked shields. I like parry, and it made me realize another thing we need rules for- defensive weapons like the main gauche.

 

[Garthanos]

Thanks a lot, I rather like those rules, though I'd be tempted to add rules for spiked shields. I like parry, and it made me realize another thing we need rules for- defensive weapons like the main gauche.

you might like Level Up

 

[James Gasik]

you might like Level Up

So people keep telling me. Now if I wasn't constantly distracted, I'd look at it more closely. : )

 

[glass]

"but acceleration is inversely proportional to mass, so it cancels out "

Correct.

The alteration due to air resistance does not simply "cancel out" unless and until you hit terminal velocity

Or even then, but I never said it did. I said that force being proportional to mass and acceleration being inversely proportional to mass cancel out, so in vacuo everything falls at a constant acceleration (assuming constant gravity). Because it does and they do.

Once you add air resistance into the equation, that technically ceases to be true, but the effect of air resistance on creatures of human size and mass is negligable. AIUI, the effect on smaller creatures is considerably less negliable.

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glass.

 

[Garthanos]

Correct.

Or even then, but I never said it did. I said that force being proportional to mass and acceleration being inversely proportional to mass cancel out, so in vacuo everything falls at a constant acceleration (assuming constant gravity). Because it does and they do.

Once you add air resistance into the equation, that technically ceases to be true, but the effect of air resistance on creatures of human size and mass is negligable. AIUI, the effect on smaller creatures is considerably less negliable.

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glass.

Cannot be correct as constants do not vary (within scope) so they are not inversely or linearly or anything else proportionate to any thing... the force remains proportionate to mass with as I agree slight reduction due to drag

F=mg.... where g does not change and mass does (as we are talking about larger vs smaller things)

 

[glass]

Cannot be correct

Can be, and is.

as constants do not vary (within scope) so they are not inversely or linearly or anything else proportionate to any thing... the force remains proportionate to mass with as I agree slight reduction due to drag

F=mg.... where g does not change and mass does (as we are talking about larger vs smaller things)

g absolutely changes, it just does not change enough to worry about for the most part, so for our current purposes we can treat it as a constant. That aside, I cannot really follow what you are saying so instead of trying to rebut it in detail I will just lay out in a bit more detail how it actually works and challenge you to rebut me:

Spoiler: The physics

Force is equal to mass x acceleration (F = ma), therefore a = F/m.

Force due to gravity = strength of gravity x mass (F = mg). This you got right.

Therefore, aceleration due to gravity = mass x strength of gravity divided by mass. Mass, being both on top and bottom of the equation, cancels (a = gm/m = g).

Therefore, acceleration due to gravity (neglecting air resistance) is independant of mass. QED.

TLDR: How fast you fall is (neglecting air resistance) completely independant of mass. Counterintuitive, but true.

Including the effects of air resistance makes things a lot more complicated, but as I understand it does not make much difference to humans (OTOH, unless they are denser than normal living creatures, creatures the size of hamsters are pretty much immune to falling damage).

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glass.

 

[Garthanos]

Can be, and is.


g absolutely changes, it just does not change enough to worry about for the most part, so for our current purposes we can treat it as a constant.

Exactly so we ignore it. you were or appeared to be claiming it is changing enough to "cancel" the change in force due to mass... it is not cancelling anything about force. (assuming force of damage from a fall)

That aside, I cannot really follow what you are saying

Your wording indicating that the constant of gravity was somehow countering/cancelling the increased force due to increase in mass. It does not.

Therefore, acceleration due to gravity (neglecting air resistance) is independant of mass. QED.
glass.

This is very much not what you said (if it were i would not dispute it and you can simply consider what you mean not in dispute just how you expressed it)

TLDR: How fast you fall is (neglecting air resistance) completely independant of mass. Counterintuitive, but true.

(also a trivial truth) And you were talking directly about force and how mass increased it but acceleration was cancelling that, ie so now it is a sudden change up and you are claiming the rest of the sentence was about velocity?

However your original statement stated A cancelled the increase in force due to mass by being inversely proportional .... and if you are looking for force (* or subsequently energy which is a better measure) from impact ie falling damage remains increased due to mass it remains higher for larger objects, (yes with g remaining close enough to the same for normal objects etc.)

 

[Garthanos]

Including the effects of air resistance makes things a lot more complicated, but as I understand it does not make much difference to humans (OTOH, unless they are denser than normal living creatures, creatures the size of hamsters are pretty much immune to falling damage).

Terminal velocity is when the acceleration due to g has been resisted completely by air resistance (you are no longer accelerating -(but get to decelerate from velocity that on impact)

That means our air resistance is not something ignorable

 

[MichaelSomething]

Now that I think about it, a DCC like character funnel would be interesting...

 

[glass]

However your original statement stated A cancelled the increase in force due to mass by being inversely proportional .... and if you are looking for force (* or subsequently energy which is a better measure) from impact ie falling damage remains increased due to mass it remains higher for larger objects, (yes with g remaining close enough to the same for normal objects etc.)

That was not my "original statement". My original statements were 1) that the mass on both side of the equation cancel, so in vacuo acceleration is independant of mass and 2) that in atmosphere this is technically no longer correct but for falling humans the difference is negliable (not so much for smaller creatures). While I have laid my position out in more detail since, i have never changed it.

Terminal velocity is when the acceleration due to g has been resisted completely by air resistance (you are no longer accelerating

Correct.

Tiny creatures are low enough mass the force of impact is low its not air resistance.

Incorrect. For the reasons now outlined at length, the only reason mass matters at all is due to air resistance.

The direct force of gravity affecting the object at the time of impact is largely irrelevant to falling damage, as can be demonstrated pretty easily: As you yourself correctly stated, F = mg. If m and g are (close enough to) constant, then so is F. If F is the same regardless of whether you fall from 1 ft or 5000 ft, then obviously F cannot directly determined damage.

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glass.