1. ## Algebra Problem

A model rocket is launched with an initial upward velocity of 235ft/s. The rocket's height h (in feet) after t seconds is given by the following.

h = 235t -16t^2

Find all values of t for which the rockets height is 151 feet. Round to the nearest hundredth.

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When doing this problem I come up with this....

h=151
151=235t-16t^2
16t^2-235t+151=0

t = 1/32 seconds

Is this correct?

2. ## Re: Algebra Problem

Originally Posted by Exfactor
A model rocket is launched with an initial upward velocity of 235ft/s. The rocket's height h (in feet) after t seconds is given by the following.

h = 235t -16t^2

Find all values of t for which the rockets height is 151 feet. Round to the nearest hundredth.

-----------

When doing this problem I come up with this....

h=151
151=235t-16t^2
16t^2-235t+151=0

t = 1/32 seconds

Is this correct?
when I plug 1/32 into your formula for h above I get 7.33 feet, so no. Use your quadratic formula roots = $\displaystyle \frac{b\pm \sqrt{b^2-4 a c}}{2 a}$

where in this case a=16, b=-235, c=151

3. ## Re: Algebra Problem

Originally Posted by Exfactor
A model rocket is launched with an initial upward velocity of 235ft/s. The rocket's height h (in feet) after t seconds is given by the following.

h = 235t -16t^2

Find all values of t for which the rockets height is 151 feet. Round to the nearest hundredth.

-----------

When doing this problem I come up with this....

h=151
151=235t-16t^2
16t^2-235t+151=0

t = 1/32 seconds

Is this correct?
Couldn't you check it yourself? What is $\displaystyle 235(1/32)- 16(1/32)^2$?