Chapter 4, Problem 39A

A sky diver steps from a high-flying helicopter. If there were no air resistance, how fast would she be falling at the end of a 12-second jump?

Distance fallen in freefall, from rest: $d=\frac{1}{2}g{t}^2$

To determine

The distance by which the sky diver falls in $12\text{}\text{s}$ if it is a free fall from rest.

Answer to Problem 39A

  $720\text{m}$

Explanation of Solution

Given:

The considered time for which the sky diver is falling freely, $t=12\text{s}$

Formula used:

The distance covered in free fall in a timetis given by,

  $d=\frac{1}{2}a{t}^2$

where, $a=g=10{\text{m/s}}^{\text{2}}$ = acceleration of free fall

Calculation:

Using the above-mentioned formula and given value, the distance by which sky diver falls freely in $12\text{s}$ will be,

  $\begin{array}{c}d=\frac{1}{2}\left(10\right){\left(12\right)}^2\\ =720\text{m}\end{array}$

Conclusion:

Hence, the vertical distance covered in $12\text{s}$ is $720\text{m}$ .