Which of the following best describes the difference between instantaneous speed and average speed?

• A. Instantaneous speed is always greater than average speed for any motion.
• B. Average speed is the speed at a particular instant, while instantaneous speed is calculated over the entire journey.
• C. Instantaneous speed and average speed are always equal for any type of motion.
• D. Instantaneous speed is the speed of an object at a specific moment in time, while average speed is the total distance traveled divided by the total time taken. $\mathrm{Average speed}=\frac{\mathrm{Total distance}}{\mathrm{Total time}}$

Answer: (D)

Verified step by step guidance

1. Understand that instantaneous speed refers to the speed of an object at a specific moment in time, capturing how fast the object is moving right then.
2. Recognize that average speed is calculated over a period of time and is defined as the total distance traveled divided by the total time taken for the journey.
3. Express the formula for average speed as \(\text{Average speed} = \frac{\text{Total distance}}{\text{Total time}}\).
4. Note that instantaneous speed can vary at different moments during the journey, while average speed gives a single value summarizing the entire trip.
5. Conclude that the key difference is that instantaneous speed is a momentary measure, whereas average speed is a measure over an interval of time.