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**Need Confirmation**

## Homework Statement

A ball is thrown upward with an initial speed of 80 ft/sec. How high does it go? What is its speed at the end of 3 sec? How high is it at that time?

## Homework Equations

v=v

_{0}+at

x=x

_{0}+v

_{0}+[tex]\Delta[/tex]t+.5a[tex]\Delta[/tex]t

^{2}

## The Attempt at a Solution

Note: Only the first equation was taught to me, my teacher isn't the best....

Because it is in ft/sec I convert it and get 24.38 m/s rounded. So..

v=24.38-9.8t [-9.8 m/s because gravity right?]

So, in three seconds the velocity is -5.02 m/s.

So, I am trying to find the max height and that occurs at 0 m/s, so I plug in 0 for final velocity.

0=24.38-9.8t

t=2.49 seconds

Then, I use the second equation:

x=0+[24.38*2.49]+0.5[-9.8*2.49

^{2}

x= 30.325 meters is the maximum height.

This is new territory for me, so I'd like to make sure I am correct. I have finals in a few days.

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