SOLUTION: Fireworks are shot upward with an initial velocity of 30 feet per second from a platform 3 feet above the ground. How long will it take the rocket to hit the ground?

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Question 30981This question is from textbook Heath Algebra 1
: Fireworks are shot upward with an initial velocity of 30 feet per second from a platform 3 feet above the ground. How long will it take the rocket to hit the ground? This question is from textbook Heath Algebra 1

Answer by Paul(988) About Me  (Show Source):
You can put this solution on YOUR website!
Next time please provide a complete information: Your formula seems to be missing here:

The formula is:

 where a is the acceleration due to gravity,v is the upward speed of the object upon release, and s is the starting height of the object and t is the seconds after being relaeased.

at the surface of the Earth a is 

Equation:

h%28t%29=-%28%2832%29t%5E2%29%2F2%2B30t%2B3

You have to solve for t:

Multiply the whole equation by -2 to remove the fraction and the negative; and simplify:

h%28t%29=32t%5E2-60t-6

Use the quadratic formula:x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

In which a=32, b=-60, c=-6

x=%28-%28-60%29%2B-sqrt%28%28-60%29%5E2-4%2A32%2A-6%29%29%2F%282%2A32%29

x=%2860%2B-sqrt%284368%29%29%2F64

Remove the negative:

x=%2860%2B66%29%2F64

Simplfy:

x=1.97

Letting x=t

t=1.97

Hence, it tool the rocket 1.97 seconds to come down.

Paul.