When two objects slide by one another, which of the following statements about the force of friction between them, is true
1. The frictional force is always equal to μkn.
2. The frictional force is always less than μkn.
3. The frictional force is determined by other forces on the objects so it can be either equal to or less than μkn.

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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 

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Answercumulus