Stop a Moving Body when a 0,0,0 force is applied

[Nutu]

I create a body, with a collision and then i check when a key is pressed:
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if(tasti[irr::KEY_KEY_W])
{
speed=500;
}
else if(tasti[irr::KEY_KEY_S])
{
speed=-500;
}
else
speed=0;
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then I apply the force on the body:

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if(speed)
{
//I take my camera target direction:
dir= camera->getTarget() - camera->getPosition();
dir.normalize();

// I Apply the force on my body.
setForce((dir*speed));

//I set the body rotation:
NewtonBodyGetMatrix(body,GetMatrixPointer(temp_mat));
temp_mat.setRotationDegrees(camera->getRotation()*IrrToNewton);
NewtonBodySetMatrix(body,GetMatrixPointer(temp_mat));


//I Update my graphics node position
nodePosition=temp_mat.getTranslation()*NewtonToIrr;
//I change the camera position
camera->setPosition( nodePosition);
vNode->setPosition(nodePosition);
//I set the actual position as previous position
prevPos=nodePosition;
moving=1;


}
else
{
moving=0;
vNode->setPosition(prevPos);
camera->setPosition(prevPos);
NewtonBodyGetMatrix(body,GetMatrixPointer(temp_mat));
temp_mat.setTranslation(prevPos*IrrToNewton);
NewtonBodySetMatrix(body,GetMatrixPointer(temp_mat));
//If i'm not moving with W,A,S,D.. etc i set a 0 Force
setForce(vector3df(0,0,0));
}
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The problem is: When i Check the force applied on my body with: [ NewtonBodyGetForce(n_body,tf2); ]while i'm not moving:
X=0, Y=0, Z=0;
but my body is still slowly moving till it stops, as in the real world when you launch an object and this is moving till the energy on it is not sufficent to move it.

The problem is that I need My body to stop when i apply a 0 Force. how can I do ?

[Julio Jerez]

if you are going to do it that way, then you can set velocity to zero when you set the force to zero.

[Nutu]

Thanks a lot Julio ^^, you was very helpfull to me
Now it works fine and i can go on with my work, (a little game project for my school ).