what is the definition of force and mass?

I see mass is measured in lindograms.

If I have a vehicle that has 100 lindograms of mass... and i set an upward force vector value of 100, will that cancel the mass and cause it to hover?

Or do I need to convert somehow. would be good to know the units of force used in SL

thx!

-Ryder-

Our friend Newton says that force equals mass times acceleration. Since the force of gravity on the object is its mass times the acceleration of gravity (9.8 should work) in the downward direction, giving it an equal force in the upward direction should make the object float.

You can also use llSetBuoyancy(1.0).

Both are somewhat unreliable.

You'll want an upward force of 9.8*llGetMass(). Since mass is measured in lindograms, we might as well say that force is measured in lindonewtons, with a lindonewton being one lindogram meter per second sqared (lg*m/s^2).

Cool... so now.... can a linked object have different prims... each with it's own "engine":

llSetForce(<0,0,thrust/4>, TRUE);

You divide the force by 4... in 4 different prims... and they add for total lift?

Or will SL not allow multiple "engine" prims in a linkset?

Thx!
-Ryder-

*KILOlindonewton-meters per second squared.

There's not really much point to putting a separate script in each linked prim. You really just need a force applied once by one script, unless the mass changes.

Well, actually there is...
you can steer a vehicle by adjusting thrust in any of the 4 motors...

Think of it as a physics exercise...

But as far as I know.. LSL does not allow it. Does anyone know for sure?

I understand what you're saying, but I don't think it works on individual prims like that while they're inside a linkset, although I'd have to try it to be sure. However, there are vehicle functions which may achieve what you're looking for, particularly an offset applied force.

9.80 meters/sec is an immutable, unchangable LAW. Except when it isn't.

http://wiki.secondlife.com/wiki/User:Andrew_Linden/Office_Hours/2008_02_28

[17:39] Andrew Linden: oh, another thing changed in the bleednig edge... I brought gravity back to 9.8 (from 9.81) so I expect a few drooping flight assists to work again (but haven't yet tested)


- Scalar Tardis / Dale Mahalko

The acceleration of gravity is not an immutable constant, and in the real world, changes slightly depending on your distance from the Earth. In reality, is it supposed to be 9.81(other missing digits) at the surface of the Earth. I don't remember whether it's always been 9.8 or 9.81 in SL, though, but in recent memory.. 9.8?

LOL. I guess. I just figred a lindogram was the equivalent of a kilogram, not a single gram.

No kind of physical movement works in child prims as far as I know. They act like non-physical objects in the root prim's reference frame. Just like physical movement functions have no effect on (non-attachment) non-physical objects, I don't think they work on child prims. I don't think it would matter anyway, as I believe energy has one value for a whole object so there wouldn't be much to gain by applying multiple forces from different prims.