It would make it go faster.
only if it is loud, and it mostly causes slow acceleration
No, If a car moves around a circular race track with any constant speed, the acceleration is directed towards the centre. So it has a centripetal acceleration. The tangential acceleration would be irrelevant unless the car has an instantaneous tangential velocity of zero. Then the centripetal acceleration is zero. However, this would only exist for that small instant in time.
Speed or acceleration have no effect on gravity.
Is stepping on the brakes of a car acceleration. That would be deceleration.
Maybe. Depends on speed of car
Acceleration does not effect gravity. It is rather the other way round. Gravity can affect the rate of acceleration.
You would need to measure the car's velocity at the top and at the bottom, and the time it took to go down the ramp. Acceleration = change of velocity/time.
There is only acceleration if the car's velocity changes. If it moves at a constant velocity, then there is no acceleration.
Acceleration simply refers to the rate of change of a velocity. You might say that the effect of an acceleration - any acceleration - is therefore a change of velocity.
According to Newton's Second Law, the "effect" (the acceleration) would depend on the objects' masses. For more mass, there would be less acceleration.
In a vacuum it does not have any effect. In a fluid, surface area, shape and texture has great effect. A small, smooth, aerodynamically designed surface area, especially the leading surface area would aid in positive acceleration. The opposite would aid in negative acceleration.
I have no clue.