Set 1 Problem number 6

• Problem

• Solution

• Generalized Solution

• Explanation in terms of Figure(s), Extension

• Figure(s)

Problem

What is the average velocityof an object that moves 20 meters in 4 seconds?

Solution

Average velocity is average displacement, in meters, in a second.

• 20 meters in 4 seconds is 5 meters in 1 second.
• So the result is 5 meters per second.

Generalized Solution

Generalized Response: Average velocity is average displacment per unit of time.

• If displacement is `ds and the time interval is `dt, then `ds / `dt is the average displacement per time unit.
• Thus vAve = `ds / `dt.

We also recognize this as the average rate at which position changes.

Explanation in terms of Figure(s), Extension

We can again use the triangular diagram to depict the relationship among `ds, `dt and vAve.

• In this case we can use vAve = `ds / `dt.

This in fact is usually taken as the definition of average velocity. It coincides with the concept of average velocity as average rate of change of position.

Figure(s)