Chapter 2.3, Problem 19PP

To determine

The distance between the runner A and runner B at $t=20\text{s}$ .

Answer to Problem 19PP

The runner A is $30\text{m}$ far apart from the runner B at $t=20\text{s}$ .

Explanation of Solution

Given info:

The position of the runner A at the time $t=20\text{s}$ is, $x_1=80\text{m}$

The position of the runner B at the time $t=20\text{s}$ is, $x_2=50\text{m}$ .

Formula Used:

The expression to calculate the displacement of the car is,

  $d=x_1-x_2$

Calculation:

Substitute the values in the above expression.

  $\begin{array}{c}d=80\text{m}-50\text{m}\\ =30\text{m}\end{array}$

Thus, the runner A is $30\text{m}$ far apart from the runner B at $t=20\text{s}$ .