The change in velocity for any time interval is zero.
Explanation
Uniform velocity refers to a state of motion where an object travels in a specific direction with a constant speed. In this state, both the magnitude and direction of the velocity vector remain unchanged over time.
Option Analysis
- Its acceleration is non-zero. is Incorrect: Acceleration is defined as the rate of change of velocity with respect to time. Since the velocity is constant (uniform), there is no change in velocity. Consequently, the acceleration is zero ($a = 0$).
- The change in velocity for any time interval is zero. is Correct: By definition, uniform velocity implies that the velocity at any instant is the same as the velocity at any other instant. Therefore, the difference between the final velocity and initial velocity ($\Delta v$) for any time interval is zero.
- Its distance-time graph is a curved line. is Incorrect: For an object moving with uniform velocity, the distance covered is directly proportional to the time taken ($s = vt$). Mathematically, this represents a linear equation, resulting in a straight-line graph with a constant slope, not a curved line. A curved distance-time graph indicates non-uniform (accelerated) motion.
- Its velocity-time graph has a positive slope. is Incorrect: The slope of a velocity-time graph represents acceleration. Since the acceleration is zero in uniform velocity, the slope of the graph is zero. The graph appears as a straight line parallel to the time axis, not a line with a positive slope.
Key Takeaway: Uniform velocity implies zero acceleration. In this state, the distance-time graph is a straight line with a constant slope, and the velocity-time graph is a horizontal line parallel to the time axis.