# yade-users team mailing list archive

## Re: [Yade-dev] moment calculation and rotational speed problem

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, [...] particle radius is 1e-3 m, one particle is static, another one is 20m/s [...] rotational_speed= rotational_speed + rotational_acceleration * dt = 0 + (5e9)*(1e-6)= 5e3 rad/sec !!!!!! WRONG!!!!
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Why wrong? If I take the translational velocity divided by the radius, it gives 20/1e-3 = 2e4 rad/s, the same order of magnitude as 5e3 rad /s. So I'd say it is consistent (imagine the mobile particle has to roll on the other one with this initial velocity, a fraction of the initial momentum is converted into rotational momentum, that is why 5e3 is lower than 2e4).
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Bruno

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_______________
Chareyre Bruno
Maitre de conference

Grenoble INP
Laboratoire 3SR - bureau E145
BP 53 - 38041, Grenoble cedex 9 - France
Tél : 33 4 56 52 86 21
Fax : 33 4 76 82 70 43
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_______________
Chareyre Bruno
Maitre de conference

Grenoble INP
Laboratoire 3SR - bureau E145
BP 53 - 38041, Grenoble cedex 9 - France
Tél : 33 4 56 52 86 21
Fax : 33 4 76 82 70 43
________________

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