Calculation of acceleration

[kidice]

Hi everybody,

i'm trying to calculate the acceleration of the user car in real time. I already tried the approach documented in this thread, which says to calculate the acceleration in the updateAction using velocity_delta / dt.

using body->getDeltaLinearVelocity() for the delta_velocity returns me always vector(0,0,0). Does anyone have an hint how to get delta_velocity or any other hint how to calculate the acceleration of a car in real time?

thank you in advance!