# College Physics 2.11 – Calculating Speed from Odometer

## Solution:

### Part A

The average speed is

$\displaystyle \text{speed}=\frac{12\:\text{km}}{18\:\text{mins}}\times \frac{60\:\text{mins}}{1\:\text{hr}}=40\:\text{km/hr}$

### Part B

The average velocity is

$\displaystyle \overline{v}=\frac{\Delta \text{x}\:}{\Delta \text{t}}=\frac{10.3\:\text{km}}{18.0\:\min \:}\times \frac{60\:\text{mins}}{1\:\text{hr}}=34.33\:\text{km/hr}$

The direction of the velocity is 25° S of E.

### Part C

The average speed is

$\displaystyle \text{speed}=\frac{12.0\:\text{km}\times 2}{7.5\:\text{hr}}=3.2\:\text{km/hr}$

And the average velocity is

$v=0$

The average velocity is zero since the total displacement is zero.