Acceleration is how fast an axis can go from no movement to some velocity in a time period. It is linear since it’s distance in a sec. It is also how fast it can increase from a current velocity to a higher velocity. The acceleration is determined by the ability of the motor to overcome the inertia of the axis. The axis usually changes circular motion to linear motion and as such it is made up of couplings, gears, belts, pulleys, a screw ( or rack and pinion), and the motor itself.
So to accelerate the motor it must have enough torque to overcome all the resistances which are trying to keep it from rotating.
A measure of that resistance is called inertia and all rotating components have it in motion and is based on their mass. Additionally other forces exist which add to the total force the motor must overcome ie; friction, efficiency of the components. You can increase the end user torque by gearing up or down, providing more energy to the system, or changing the system makeup ( different screws or pitch), etc.
The longer the time to accelerate to some velocity the flatter the angle will be in motor tuning. It takes a lot of Force to move a big mass from standstill to a high velocity in a short time period. The amount of torque / force available from the motor is not infinite
within the motors capability. It takes energy to rotate the motors shaft.
That said , you will need to find an appropropiate accel value when tuning your motors.
RICH