A ball is thrown upward from a height of 15 ft with an initial velocity of 5 ft/s. Use the equation h=-16t^2+5t+15 to answer the following questions. Round to the nearest tenth.…

Question

asked Dec 7, 2023 104k views

1 Answer

Xiao Luo · Answer 1 · 2023-12-11T02:55:03+0000

Answer:

1) 1.1 seconds

2) 13.5 feet

$\rightarrow \sf -16t^2 + 5t + 15 = 0$

Apply quadratic formula:

$\rightarrow \sf t= (-5\pm √(5^2-4\left(-16\right)\cdot \:15))/(2\left(-16\right))$

Simplify following

$\rightarrow \sf t=-(-5+√(985))/(32),\:t=(5+√(985))/(32)$

In decimal form:

$\rightarrow \sf t=-0.825 ,\:t=1.137$

Conclusion:

As time is be only positive: t = 1.1 seconds

$\rightarrow \sf h=-16t^2 + 5t + 15$

insert t = 0.5

$\rightarrow \sf h=-16(0.5)^2 + 5(0.5) + 15$

simplify

$\rightarrow \sf h=13.5$