Question

If an object is dropped from a height of 144 feet, the function h(t)= -16t^2+144 gives the height of the object after t seconds. When will the object hit the ground?

A. 9 s
B. 6 s
C. 1.5 s
D. 3 s

Answer 1

well, solve the equation for h = 0...what positive value of t makes it so?

Answer 2

at t = 0, h(0) = -16(0)^2 + 144 = 144 feet, which is the height from which it is being dropped. at some later t, h(t) = 0, and that's when it hits the ground.

Answer 3

\[h(t) = 0 = -16t^2+144\]\[16t^2=144\]\[t=\]

Answer 4

so it 9

Answer 5

does 16*9*9 = 144?

Answer 6

always, always check your answers in the original formula to make sure they correctly answer the question.

Answer 7

no

Answer 8

its 3

Answer 9

it is 3 gj

Answer 10

16(3)(3) = 144, so that is a reasonable answer. Note that t = -3 also satisfies the equation, but does not satisfy the conditions described in the problem, so it is not a correct solution here.

Answer 11

ok