IMHO, there is only one KE of a system, and it is defined by:

the sum (integral) on all the system of the products mass X velocity^2 of

every point of mass of the system.

Therefore:

If the system is translating (ie every point of mass has the same vectorial

speed) then to compute its KE it is easier to use 1/2*M*V*V. And if it

rotates, you can use 1/2*I*W*W.

If the system is composed of subsystems, you can compute the KE of each

subsystem. The KE of the system is the sum of the KE of each subsystem.

If you split the movement of the system in a part of translation of CoG and

a rotation around the CoG, you can compute separately the KE of the

translation and the KE of the rotation, and add both to find the KE of the

whole system.

If the system translates at a speed, which has components in the three

directions x,y,z (vx, vy, vz) then you can compute the KE of each component,

and then add them: KE=KEx+KEy+KEz.

Patrick

Patrick Maillard

Institut de Recherches Robert BOSCH SA

PO BOX 12, Route de Denges 2

CH-1027 LONAY, SWITZERLAND

phone: ++41 21 804 72 17

fax: ++41 21 804 72 05

e-mail: Patrick.Maillard@ch.bosch.com

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the sum (integral) on all the system of the products mass X velocity^2 of

every point of mass of the system.

Therefore:

If the system is translating (ie every point of mass has the same vectorial

speed) then to compute its KE it is easier to use 1/2*M*V*V. And if it

rotates, you can use 1/2*I*W*W.

If the system is composed of subsystems, you can compute the KE of each

subsystem. The KE of the system is the sum of the KE of each subsystem.

If you split the movement of the system in a part of translation of CoG and

a rotation around the CoG, you can compute separately the KE of the

translation and the KE of the rotation, and add both to find the KE of the

whole system.

If the system translates at a speed, which has components in the three

directions x,y,z (vx, vy, vz) then you can compute the KE of each component,

and then add them: KE=KEx+KEy+KEz.

Patrick

Patrick Maillard

Institut de Recherches Robert BOSCH SA

PO BOX 12, Route de Denges 2

CH-1027 LONAY, SWITZERLAND

phone: ++41 21 804 72 17

fax: ++41 21 804 72 05

e-mail: Patrick.Maillard@ch.bosch.com

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To unsubscribe send SIGNOFF BIOMCH-L to LISTSERV@nic.surfnet.nl

For information and archives: http://isb.ri.ccf.org/biomch-l

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