Question

Joseph jogs from one end A to the other end B of a straight 300 m road in 2 minutes 30 seconds and then turns around and jogs 100 m back to point C in another 1 minute. What are Joseph's average speeds and velocities in jogging from A to B?

Answer 1

Step 1: Given parameters

For motion from A to B,

Total distance, $\mathrm{AB}=300\text{m}$

Displacement, $\mathrm{AB}=300\mathrm{m}$

Total time, $t$

$$\begin{gathered} t=2\mathrm{minutes}30\mathrm{seconds} \\ t=2\times 60\mathrm{seconds}+30\left(\because 1\mathrm{minute}=60\mathrm{seconds}\right) \\ =150\text{s} \end{gathered}$$

Step 2: Calculate the average speed

Calculate the average speed of Joseph as follows:

$$\begin{gathered} \text{Average speed}=\frac{\text{Total distance}}{\text{Total time}} \\ =\frac{300\text{m}}{150\text{s}} \\ =2\mathrm{m}/\mathrm{s} \end{gathered}$$

Step 4: Calculate the average velocity

Calculate the average velocity of Joseph as follows:

$$\begin{gathered} \mathrm{Average}\mathrm{velocity}=\frac{\text{displacement}}{\text{Total time}} \\ =\frac{300\text{m}}{150\text{s}} \\ =2\mathrm{m}/\mathrm{s} \end{gathered}$$

Hence, the average speed is $2\mathrm{m}/\mathrm{s}$ and average velocity is $2\mathrm{m}/\mathrm{s}$.