Question

help? anyone?
The function y = -16t2 + 486 models the height y in feet of a stone t seconds after it is dropped from the edge of a vertical cliff. How long will it take the stone to hit the ground? Round to the nearest hundredth of a second.




A. 11.02 seconds


B. 0.25 seconds


C. 7.79 seconds


D. 5.51 seconds

Answer 1

u just need to plug y = 0 and solve equation for t

Answer 2

@emmaleelooney there??

Answer 3

HI!!

Answer 4

\[ -16t^2 + 486 =0\] or \[16t^2=486\]

Answer 5

divide by 16, take the square root of the result

Answer 6

First thing to do is solve T first.

\[y=−16t^2+486\]
~~~~~~~~~~~~~~

The first step is to flip the equation.

\[−16t^2+486=y\]
~~~~~~~~~~~~~~~
The we would have to

Add -486 to both sides.
~~~~~~~~~~~~~~~~~~~~

\[−16t^2+486+−486=y+−486\]
\[−16t^2=y−486 \]
~~~~~~~~~~~~~~~~~~~~~~~~~~~

After we added both of the sides, now we are going to divide both sides by \[-16\].

\[−16t^2 −16 = y−486 −16 t^2= −1 16 y+ 243 8\]

Last step!

Take square root.
\[ t=√ −1 16 y+ 243 8 or t=−√ −1 16 y+ 243 8\]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Answer is-

\[t=√ −1 16 y+ 243 8 or t=−√ −1 16 y+ 243 8 \]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I hoped I helped you with your question!

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