Question

How long would it take a ball dropped from a 100 ft building to hit the ground

Answer 1

now, if the ball is just free-falling, is simply dropped from 100ft, then the initial velocity is 0, and the initial height is 100, and it hits the ground when its height reaches 0.


`\bf \qquad \textit{initial velocity}\\\\ \begin{array}{llll} \qquad \textit{in feet}\\\\ h(t) = -16t^2+v_ot+h_o \\\\ \end{array} \quad \begin{cases} v_o=\textit{initial velocity of the object}\\ h_o=\textit{initial height of the object}\\ h=\textit{height of the object at`


`\bf t^2=\cfrac{100}{16}\implies t^2=\cfrac{25}{4}\implies t=\sqrt{\cfrac{25}{4}}\implies t=\cfrac{√(25)}{√(4)}\implies t=\cfrac{5}{2}~secs`