I Will Give Medal!!!!

Tiffany kicks a soccer ball off the ground and in the air with an initial velocity of 28 feet per second. Using the formula H(t)=-16^2+vt+s, what is the maximum height the soccer ball reaches?

A. 15.6 feet
B. 14.1 feet
C. 13.5 feet
D. 12.3 feet

Question

I Will Give Medal!!!!


Tiffany kicks a soccer ball off the ground and in the air with an initial velocity of 28 feet per second. Using the formula H(t)=-16^2+vt+s, what is the maximum height the soccer ball reaches?

A. 15.6 feet
B. 14.1 feet
C. 13.5 feet
D. 12.3 feet

jlg030597 · Answer

Whats your guess buddy

jlg030597 · Answer

Ill help you get to the answer if your wrong

anonymous · Answer

Honestly I forget how to use the formula.

mathmale · Answer

Are you sure it's H(t)=-16^2+vt+s?     do you want that "v" in there, or was that a typo?

anonymous · Answer

yes the v is in the problem

mathmale · Answer

And that's an "s" ?

With two unknowns, it's pretty difficult to estimate what the max height would be.  

If you had H(x) = -16t^2 + 28t + 5 (the 5 arbitrary), you could graph H(x) and easily find the max height.  But without knowing the value of " s ", you can't.  Double check, please, that you're copied the problem down correctly.

mathmale · Answer

Is this course "algebra" or "calculus"?

anonymous · Answer

I think they put the s there so that it would get replaced like by that 5. this is algebra 1

mathmale · Answer

that "s" represents the INITIAL HEIGHT of the soccer ball.  Obviously it's not going to be a very large number, since most of us could not kick a soccer ball that was more than about 5 feet in the air, right?

If v = initial velocity = 28 (ft/sec), then your equation becomes APPROXIMATELY 

H(t) = -16*t^2+28t+5.

Note that you didn't include the t^2 earlier, so I've fixed that.

Now, if you'd graph H(t) = -16*t^2+28t+5, you could see pretty easily what the maximum height will be.  Sound OK?

anonymous · Answer

yeah ok

mathmale · Answer

Are you now able to estimate the max. ht.?

mathmale · Answer

I've graphed this function on my TI-83 Plus calculator and see that the graph is a parabola that opens down.  Using the Trace function, it's easy to determine the approx. max. height reached by the soccer ball.  For s = 5 feet, I get max. ht. = approx. 17 feet.  That's reasonable for a soccer ball kick, isn't it?  Maybe you can kick a soccer ball 100 ft into the air; sadly, I can't.

anonymous · Answer

Haha alright so is that it is 17 the anwser

mathmale · Answer

Won't say!  You'll have to decide that for yourself!

anonymous · Answer

Well I guess not being that its not any of the choices haha

mathmale · Answer

Choose the answer choice that makes the most sense to you, even if it's not exactly 17 ft!