Chapter 2.1, Problem 2PP

To determine

The time taken by the motorcycle to travel a distance of 10 km.

Answer to Problem 2PP

The required time is $\boxed{t=250\text{s}}$ .

Explanation of Solution

Given:

The speed of a motorcycle is $s=40\text{m/s}$ .

The distance is $d=10\text{km}$ .

Formula used:

The expression of speed is

  $s=\frac{d}{t}$....................(1)

Here, $d$ and $t$ are distance and time respectively.

Calculation:

Equation (1) can be rearranged as,

  $t=\frac{d}{s}$....................(2)

Substitute $10\text{km}$ for $d$ and $40\text{m/s}$ for $s$ in equation (1)

  $\begin{array}{l}t=\frac{10\text{km}}{4\text{0}\text{m/s}}\\ t=\frac{10\text{km}\times \left(\frac{1000\text{m}}{1\text{km}}\right)}{4\text{0}\text{m/s}}\\ t=\frac{10000\text{m}}{4\text{0}\text{m/s}}\\ \boxed{t=250\text{s}}\end{array}$

Conclusion:

Hence, the required time is $\boxed{t=250\text{s}}$ .