How to set kinetic friction force to a wheel joint in a car

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Hi, pros. I'm a newbie of Gazebo simulation. I'd like to ask for your advice on how to kinetic friction force to a wheel joint in a car. What i'm using to push a car run is two function:

this->joints[i]->SetVelocity(1,max(0,(gas-brake)*C);

this->joints[i]->SetMaxForce(1, (gas +brake) * this->rearPower);

(in which gas and brake are changed during test. Others are stable).

I suppose that while my car is running at a velocity V, if i gas and brake i Zero, then my car should run slower graduately due to dynamic friction force to stop. But i don't know how to set this condition.

Please help me to figure it out. Thanks.