Chapter 9, Problem 5MCQ

To determine

Tofind:Time taken by object to reach ground

Answer to Problem 5MCQ

  $2\mathrm{seconds}$

Explanation of Solution

Given information:

Height of tower $d=24.1\text{ meter}$

Time $t$

  $d=4.9t^2$

Calculation:

Let’s substitute the height of tower in given formula-

  $\begin{array}{l}d=4.9t^2\\ \Rightarrow 24.1=4.9t^2\\ \Rightarrow t^2=\frac{24.1}{4.9}\\ \Rightarrow t^2=4.918\\ \Rightarrow t=\sqrt{4.918}\\ \Rightarrow t=2.21\\ t\approx 2\mathrm{seconds}\end{array}$