Are the Material Properties in My Physics Library Accurate?

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Homework Help Overview

The discussion revolves around the accuracy of material properties such as density, friction, and restitution for various materials in a physics library intended for application development. The original poster seeks validation of these properties.

Discussion Character

  • Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants question the intrinsic nature of friction and restitution coefficients, suggesting they can vary based on conditions. Others raise concerns about the variability of wood properties depending on species.

Discussion Status

The discussion is ongoing, with participants providing insights into the variability of material properties and questioning the assumptions made by the original poster. No consensus has been reached regarding the accuracy of the provided values.

Contextual Notes

There is an acknowledgment of the potential variability in material properties based on external factors and specific material types, particularly for wood.

RicardoTk
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Hi everyone!

Im developing an application with a physics library.

In the application I pre-setted some materials with the following properties,

Density, Friction and Restitution

Im not sure if this informations are truly trustable,

Can you guys just review this for me?

===|Wood|==
Density: 680 kg/m³
Friction: 0.4
Restitution: 0.7

===|Iron|==
Density: 7400 kg/m³
Friction: 1 (Steel = 0.8 )
Restitution: 0.85

===|Concrete|==
Density: 2300 kg/m³
Friction: 0.65
Restitution: 0.75

===|Rubber|==
Density: 920 kg/m³
Friction: 0.75
Restitution: 0.3

===|Polystyrene|==
Density: 80 kg/m³
Friction: 0.5
Restitution: 0.5

===|Plastic|==
Density: 1300 kg/m³
Friction: 0.35
Restitution: 0.6

References:
http://www.matbase.com/
http://www.matweb.com/
http://physics.info/density/
http://www.bulletphysics.org/Bullet/php ... ?f=9&t=616
http://www.woodweb.com/knowledge_base/W ... dbook.html
http://www.engineershandbook.com/Tables ... cients.htm
http://www.engineeringtoolbox.com/frict ... d_778.html
http://hypertextbook.com/facts/2006/restitution.shtml

Thanks!
 
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I can't tell you if these values are correct, but the coefficient of friction and (probably) the coefficient of restitution are not intrinsic properties of the materials. Think about it, the same rubber tires will stop in a shorter distance on dry asphalt than on wet, and a basketball will bounce higher on cement than on shag carpeting.
 
How accurate do they need to be because the properties for wood vary by a factor of at least 2 depending on species.
 
Thank you guys! :cool: