Trouble with button accelerate on face, simulate car

hi
I’m trying to create a button when you press the button the sphere accelerate forward y keep going until the button is released, and keep going by the force and friction
this sphere also move with the character controller using these references

this what I have but don’t work
if (Input.GetButton(“Fire1”))
{
m_Rigidbody.AddForce(transform.forward * friction);
}
thanks

i create some variable rate, velocity, and final velocity also decelerate value zo this is the code now works
thanks to Acceleration script - Questions & Answers - Unity Discussions
still trouble with decelerate but okk

 if (Input.GetButton("Fire1"))
                {  
                 //add to the current velocity according while accelerating
                   currentVelocity = currentVelocity + (accelerationRate * Time.deltaTime);
                   transform.Translate(currentVelocity, 0, 0);
                 }
                 else
                  if(currentVelocity > 0) {
                      currentVelocity = currentVelocity - (decelerationRate * Time.deltaTime);
                      transform.Translate(currentVelocity, 0, 0);
                  }
                  else {
                      transform.Translate(0, 0, 0);
                  }
                  currentVelocity = Mathf.Clamp(currentVelocity, initialVelocity, finalVelocity);
                    //propel the object forward
                  transform.Translate(currentVelocity, 0, 0);
    }