Chapter 11.1, Problem 2E

Solution

To find: the average velocity.

The average velocity during the entire 4.5 hours is 120 kmph.

Given information:

An automobile travels 540 km in 4 hours 30 min.

Formula used:

Average velocity is the change in position divided by the change in time.

Calculation:

The average velocity is the change in position (540 km) divided by the change in time (4.5 hours). Denote position by $s$ and time by $t$ , then

  $\begin{array}{c}{v}_{ave}=\frac{\Delta s}{\Delta t}\\ =\frac{540\text{ km}}{\text{4}\text{.5 hr}}\\ =120\text{ kmph}\end{array}$

Thus, the average velocity during the entire 4.5 hours is 120 kmph.