if you were to accellerate strongly(foot to floor) to 100mph and at 100mph dip the clutch, then you would still accelerate for a few seconds, but it would not be as fast, so you would probably ony get to 103/104mph, after this you would decellerate due to friction and wird resistanc, but you would still be accellerating and the rate of accelleration would be less until you decellerate... its not an on/off switch... you can have periods of no accelleration and no decelleration...