Question

greg is in a bike race. at mile marker four (out of ten), his speed was measured at 13.5 mph. which best describes the measured number? it is the average speed of the bike rider. it is the instantaneous speed of the bike rider. it is the instantaneous velocity of the bike rider. it is the average velocity of the bike rider.

Explanation:

Average speed/velocity is calculated over a period or distance. Instantaneous speed is the speed at a specific point. Here, speed is measured at a specific mile - marker (mile marker four), not over a distance or time interval for average calculation. Also, speed only has magnitude while velocity has magnitude and direction. Since only magnitude (13.5 mph) is given, it's speed not velocity.

Answer:

It is the instantaneous speed of the bike rider.