Have I Got Jumping Velocity Right?

[Refplace]

Originally Posted by vitruvian

And the thing is, I like the turtles and it seems like if they're leaping that far they should hit pretty hard.

I like the turtles too :) I have made jumping tree frogs that use slam but really I think I have otherwise seen this only in Supers.
I think they are the most original monster in the adventure and would be fun to use.
However slam is one of those things that IMHO needs a little rewrite and more work in GURPS. I wish we had a book out that redid them. Even a pyramid article.

[vitruvian]

Originally Posted by Refplace

I like the turtles too :) I have made jumping tree frogs that use slam but really I think I have otherwise seen this only in Supers.
I think they are the most original monster in the adventure and would be fun to use.
However slam is one of those things that IMHO needs a little rewrite and more work in GURPS. I wish we had a book out that redid them. Even a pyramid article.

In this case, it's not the Slam damage formula so much as the rules for Super Jump, I think. With regard to the variant rule I suggested upthread, it looks like the numbers change less from existing jumps if you make the divisor 6 rather than 5, but I like the symetry of having a 'Basic Jump' figured in the same way that Basic Lift is.

So, here's what I'll try next time I run - your Running Broad Jump starts off equal to your Basic Move^2/5; distance is halved (and velocity is two-thirds, rounded down) for a standing jump, and high jump is half that. With Super Jump, each level doubles distance and increases effective Move by 1.5 (rather than 1.4, for simplicity's sake); each two levels quadruple distance and double Move. That would mean a Move 3 creature could normally jump not even quite two yards, but with Super Jump 4 actually travels over 28 yards going at an effective Move 12.

[DouglasCole]

Originally Posted by vitruvian

So, here's what I'll try next time I run - your Running Broad Jump starts off equal to your Basic Move^2/5;

When I went through the physics for the range of bows and arrows for my Low Tech Pyramid article, the distance the arrow flies is proportional to velocity directly, rather than the square of it. Makes things simpler.

[vitruvian]

Originally Posted by DouglasCole

When I went through the physics for the range of bows and arrows for my Low Tech Pyramid article, the distance the arrow flies is proportional to velocity directly, rather than the square of it. Makes things simpler.

That works out for a flat trajectory, but not for a parabola like the Hulk jumping 3 miles.

[lexington]

Originally Posted by munin

I can't figure out how the slam damage is calculated at all. If 4d+4 equals 5.2 dice, then the slam damage formula (with HP = 45) implies a velocity of 11.5?

The always AoA-Strong.

3.6 dice for 8 yards per second rounds up to 4 under the slam rules, +1 per die for AoA-Strong.

[Refplace]

Ok ruling from Kromm.

Originally Posted by Kromm

People are simply missing that DF is a specific genre treatment. A lot of the more complicated rules in GURPS in general are ignored for that series. One such rule is resolving jumps over several turns . . . seriously, that would be boring for heroes who have that ability (like martial artists, for instance). "Still jumping . . ." for up to five turns?

So there's no erratum here, any more than it's an error that we allow more than four levels of Talent in DF, or make most advantages learnable in play, or use a different jumping formula in DF 2.

So it appears that they get to move their full move in 1 turn as a genre convention. Which is fine and after all waiting for a few turns to land while realistic IS boring.
So if they get to move the full distance in 1 turn that changes their velocity and it all works out.
Wonder if that could be an enhancement for Supers games and what % it would be. +50% Cosmic to ignore a rule? That matches the instant acceleration on Enhanced Move too.
yep. off to rebuild my tree frogs I think..... (they were done right but just jumped shorter distance unless surprising you. This just makes them cooler.)

Edit: By the way I do not have DF 2. Different jumping formula? Someone should have mentioned that in this thread. Does the math work with it?

[DouglasCole]

Originally Posted by vitruvian

That works out for a flat trajectory, but not for a parabola like the Hulk jumping 3 miles.

??? It works out for arrows shot into the air with a bow, which is fairly parabolic, I believe.

[munin]

Originally Posted by Refplace

Edit: By the way I do not have DF 2. Different jumping formula? Someone should have mentioned that in this thread. Does the math work with it?

"If an obstacle is ... wide, it calls for an expert with the Jumping skill, who can run and jump up to skill/2 yards." (p. DF2-7). That's about if for jumping distance rules (but there's some acrobatic stuff too). It means you don't have to do jumping distance calculations, you can just use skill/2 yards. And anyone who doesn't have Jumping skill can't, I guess. The Greater Bounding Turtle doesn't have Jumping skill and DF2 doesn't mention Super Jump so it didn't seem relevant.

[Refplace]

Originally Posted by munin

"If an obstacle is ... wide, it calls for an expert with the Jumping skill, who can run and jump up to skill/2 yards." (p. DF2-7). That's about if for jumping distance rules (but there's some acrobatic stuff too). It means you don't have to do jumping distance calculations, you can just use skill/2 yards. And anyone who doesn't have Jumping skill can't, I guess. The Greater Bounding Turtle doesn't have Jumping skill and DF2 doesn't mention Super Jump so it didn't seem relevant.

That is an interesting change. Basic has it skill/2 can be sued to replace Basic Move in the formula. Your right, no difference here but I appreciate you letting me know, DF 2 is on my list but not a top priority, though I have picked up others in that series.

[seasong]

The optimal broad jump distance has equal vertical and horizontal velocity, which makes it easy to calculate velocity. Take your maximum broad jump distance:

Velocity = the square root of (distance in yards x 5).

Hang-time is distance divided by horizontal velocity; or vertical velocity x 0.2. Both come out to the same value, use whichever is easier for you.

Vertical distance uses the Falling Velocity Table on p. B431. Look down the velocity column and find your velocity, then shift over to the fall column to find out how high you went at the mid-point of the broad jump.

Example: Kermit
Kermit has Move 3 and Super Jump 6. This gives him a broad jump of 64 yards. His vertical and horizontal velocity is 17.9 yards per second (giving him a hang-time of 3.58 seconds, and a vertical height of 15 yards).

With a running start, Kermit can manage a broad jump of 128 yards. Velocity is 25.3 yards per second (hang-time 5 seconds, vertical height 28 yards).

Example: Hulk
Hulk has Move 10 and Super Jump 11. This gives him a broad jump of 4,800 yards (or 2.7 miles). His vertical and horizontal velocity are 155 yards per second (giving him a hang-time of 31 seconds, and a vertical height of 1,123 yards, or 0.6 miles).

With a running start, Hulk can manage a broad jump of 9,600 yards. Velocity is 219 yards per second (hang-time 43.8 seconds, vertical height 2,240 yards).

Note: Realistically, Hulk's leaps exceed terminal velocity. With a torpedo-like shape and human density, terminal velocity of 100 yards per second caps the maximum broad jump at 2,000 yards (1.1 miles).