setLinearVelocity Function ?

[Youne]

Hi Everybody,

I noticed something which seems a little odd to me and I would really like to have some explications for this. The function setLinearVelocity allows us to apply a linear Velocity to a rigidbody. I did the following tests which entails applying a Velocity to :
1st case: a single object with a mass M
2nd case: to the same object linked by a constraint to another object of any mass M'.

in the 1st case : it's fine
in the 2nd case : I realised that the object does not move with the velocity which we applied on it (and in addition this velocity also depends on the mass of the second object M'.)

My aim in this model is to apply a constant velocity to an object linked to another (like Hydraulic jack). Therefore I would like to know how I should proceed? Because in my opinion the function setLinearVelocity is not the appropriate function to achieve this!

Thank you for your Help

Youne