Asubtence floats or sinks in onother becauseof its relitivity

No.  A substance floats or sinks in another substance because of
the densities of both of them.

If the density of the substance is more than the density of the other
one, it will sink.  If less than the density of the other one, it will float.

Answertraveling around a circular trackexplanation"traveling around a circular track" is the best answer as you could be traveling around a circular track at a constant speed. your velocity would therefore have the same magnitude but will always be constantly direction. since acceleration is the rate of change of velocity, the rate of change will only involve the direction of velocity and not the magnitude.wrong choices: "an object at rest" does not accelerate at all"increasing speed while traveling around a curve" means that the acceleration will not be constant due to only change in direction; it will be constant due to both magnitude and direction"an object in free fall" does not necessarily change direction