Chapter 2, Problem 51R

(a)

To determine

To Find:The average speed of the cyclist.

Answer to Problem 51R

The speed of the cyclist is $\text{22}\text{.4}\text{km/h}$

Explanation of Solution

Given:

Distance travel by the cyclist is $45\text{km}$

Entire tripe time is $\text{4}\text{h}$

Formula:

Average speed of an object is given by

  $s\text{=}\frac{d}{t}$

Here, $s$ is speed, $d$ is distance and $t$ is time.

Calculation:

The cyclist travel distance at $\text{4}\text{h}$ is $45\text{km+45}\text{km}\text{=}\text{90}\text{km}$

Therefore its speed is

  $\begin{array}{l}=\frac{\text{90}\text{km}}{\text{4}\text{h}}\\ \text{=}\text{22}\text{.4}\text{km/h}\end{array}$

Conclusion:

Hence, the speed of the cyclist is $\text{22}\text{.4}\text{km/h}$

(b)

To determine

To Find:The displacement travel by the cyclist.

Answer to Problem 51R

The displacement of the cyclist is $\text{0}\text{km}$

Explanation of Solution

Given:

Distance travel by the cyclist is $45\text{km}$

Entire tripe time is $\text{4}\text{h}$

Calculation:

Science the cyclist travel at a point and then return to the initial point so the displacement of the cyclist in $\text{4}\text{h}$ is $45\text{km-45}\text{km}\text{=}\text{0}\text{km}$ .

Conclusion:

Hence, the displacement of the cyclist is $\text{0}\text{km}$