SOLUTION: height of rocket launched from platform 12 meters above ground is modeled by function h=-1.4t+25t+12 where h represents height of rocket in meters and t represents number of second
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Question 431079: height of rocket launched from platform 12 meters above ground is modeled by function h=-1.4t+25t+12 where h represents height of rocket in meters and t represents number of seconds after launching. how many seconds after launching will rocket return to ground?
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
No.
The height of a projectile in meters, 
seconds after being launched from an initial height of 
at an initial vertical velocity of 
is given by:
\ =\ -4.9t^2\ +\ v_ot\ +\ h_o)
presuming, of course, that all of this activity is occuring in the vicinity of the planet Earth. I can't imagine where you came up with a -1.4 as a lead coefficient (too big for the moon and too small for Mercury or Mars...maybe one of Jupiter's moons) and I can't imagine how you can have distance as a function of time with a constant acceleration without having a squared variable.
Your problem has an initial velocity of 25 meters/second and an initial height of 12 meters, so:
\ =\ -4.9t^2\ +\ 25t\ +\ 12)
You are concerned with finding the positive value of when the projectile returns to the ground which is typically considered to be 0 height.
Hence:
\ =\ 0)
which is to say:
Just use the quadratic formula to solve the quadratic for the positive root.
John
My calculator said it, I believe it, that settles it
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