
Amanda Z. answered 10/10/17
Tutor
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Master the Fundamentals of Science and Math
Ignoring typos and simply considering the equation...
Height (H) is 0 when the object reaches the ground
H = 0 = -16t2 + 672
Divide both sides by -16:
0 = t2 - 42
Move the constant to the others side:
42 = t2
Take the square root:
±6.48 = t
We can't have a negative time to land, so
t = 6.5, or 6 1/2 seconds to land
Divide both sides by -16:
0 = t2 - 42
Move the constant to the others side:
42 = t2
Take the square root:
±6.48 = t
We can't have a negative time to land, so
t = 6.5, or 6 1/2 seconds to land