Answer:
30 seconds.
Explanation:
So, we have the equation:
![h(t)=-16t^2+h](https://img.qammunity.org/2021/formulas/mathematics/high-school/ibk61ez79bkp1e4hr2etjqv4ro15yx41ci.png)
Where t is the time in seconds and h is the initial height.
A barometer falls from a weather balloon at a height of 14,400 feet. In other words, the initial height is 14,400. Substitute for h:
![h(t)=-16t^2+14400](https://img.qammunity.org/2021/formulas/mathematics/high-school/ojuov35o9oygguf4dz5baloo6sc1rsgso4.png)
We need to find when the barometer hits the ground. Ground level is 0 feet. Therefore, we can substitute h(t) for 0 and solve for the equation (solve for t) in order to find how long (in seconds) it took for the barometer to fall:
![0=-16t^2+14400\\-14400=-16t^2\\900=t^2\\t=\pm√(900) \\\text{Time cannot be negative.}\\t=√(900)\\ t=30 \text{ seconds}](https://img.qammunity.org/2021/formulas/mathematics/high-school/riis5bc82q8v4ou7am5ledi6jk1j8qd856.png)
Therefore, it took 30 seconds for the barometer to hit the ground when it fell at a height of 14,400 feet.
Edit: Spelling.