Question

an egg is dropped from a height of 90 ft. if acceleration due to gravity is -16 ft/s² and initial velocity is 0 ft/s, approximately how long will it take for the egg to reach the ground?
h(t)=at² + vt + h₀
1.9 s
2.4 s
9.7 s
40.7 s

Explanation:

Step1: Identify the values

Given $a=- 16$ ft/s², $v = 0$ ft/s, $h_0=90$ ft and when the egg reaches the ground $h(t)=0$. Substitute into $h(t)=at^{2}+vt + h_0$.
$0=-16t^{2}+0\times t + 90$

Step2: Solve for $t$

$16t^{2}=90$
$t^{2}=\frac{90}{16}$
$t=\sqrt{\frac{90}{16}}\approx\sqrt{5.625}\approx2.4$ s

Answer:

2.4 s