That's begging the question a little bit, as acceleration is absolute only because we restrict ourselves to inertial (i.e. lacking acceleration) reference frames. If you allow non-inertial reference frames, acceleration can be relative - Coriolis acceleration, for instance, may be nonzero relative to a rotating reference frame but zero in inertial coordinates.
@khird @sda @mandlebro @mngrif
So if we look at position and all its derivatives we see:
Position - relative
Velocity (1st derivative) - relativederrivative
Acceleration (2nd derivative) - non-relative
Jerk (3rd derivative) - non-relative
Every additional derivative is also non-relative...
Sort of. Acceleration isnt force though. It is however the result of a force applied to a mass.
Otherway around. If you sitting in a ship and want to know the force applied to the ship as well as the acceleration it is undergoing you would directly measure acceleration and then can find the force applied to the ship if you know or determine the ships mass
If you had a spring and a standard mass (known to be 1kg or something) inside the ship with you and you used that to measure you would not be measuring the force applied to the ship but rather the force applied to teh weight attached to the spring, which would be an entierly different quantity of force than the force applied to the ship.
So its a little convoluted in practice we would use a fixed weight and spring to determine acceleration from the force applied to the fixed weight, and then from that acceleration use it to determine the force applied to the ship (if you know the ships mass).
But it might help give you some insight on the relationship between force and acceleration if you consider how we might measure it if we didnt know anything about mass. If you stick some unknown mass in a tube and obsere how fast it accelerates from one end to the other then we know the acceleration on the ship directly. In this setup the mass in the tube doesnt need to be known as all masses would behave the same.
@freemo @khird @sda @mngrif I see. All the non relative things depend on force which can be measured without a fixed reference frame. The constant you pick when integrating acceleration is the first one that represents a point in space. Never really thought about that.