Question

A squirrel in a tree drops an acorn. how long does it take the acorn to fall 20 feet?

Answer 1

We use the equation of motion,

$S= ut+\frac{1}{2}at^{2}$

Here, S is the height, u is initial velocity and a is acceleration.

Given, $S = 20 \ ft$ $S = 20 \ ft = 20 \times\frac{1 \ m}{3.2808399 ft} = 6.096 \ m$

As  acorn falls from tree, therefore we take the value of $a = 9.8 \ m/s^2$ and initial velocity $u = 0$.

Substituting these values in equation of motion,

$6.096 \ m = 0 \times t +\frac{1}{2} \times 9.8 m/s^2 (t)^2 \\\\\ t = 1.12 \ s$

Thus, the time taken by the acorn to fall 20  feet ( 6.096 m ) is 1.12 s.