Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

What distinguishes instantaneous speed from average speed?

1. Instantaneous speed is always higher than average speed

2. Instantaneous speed is speed measured at a specific moment

3. Average speed is never zero

4. Instantaneous speed is the average of speeds over multiple instances

The correct answer is: Instantaneous speed is speed measured at a specific moment

The distinction between instantaneous speed and average speed lies primarily in the way each measure is defined in relation to time intervals. Instantaneous speed is defined as the speed of an object at a specific moment in time. This can be visualized as the speed indicated on a speedometer in a vehicle at any given instant. It reflects the immediate rate of motion without regard to the path taken or the duration of travel. In contrast, average speed is calculated over an interval of time, considering the total distance traveled divided by the total time taken for that journey. This means average speed encompasses the entire trip and can involve varying velocities throughout that time. This clear differentiation highlights why the correct answer captures the essence of instantaneous speed, focusing specifically on the moment it is measured rather than over an extended duration.