Question

A chestnut falls out of a tree 45 feet above the ground. Use the vertical motion model, H=-16t^2+vt+s s to find how long it takes to hit the ground. Round your answer to the nearest tenth. Remember to include units in your answer.

Answer 1

Answer:

1.7 seconds

Step-by-step explanation:

we have

$H=-16t^2+vt+s$

where

v is the initial velocity (in feet per second)

s represents the initial height (in feet)

In this problem we have

$v=0$ ---> because the object is dropped

$s=45\ ft$

substitute

$H=-16t^2+45$

Remember that

When the chestnut hit the ground the value of H is equal to zero

so

For H=0

$-16t^2+45=0$

solve for t

$16t^2=45\\t^2=2.8125\\t=\pm1.7\ sec$

therefore

The solution is t=1.7 sec