SOLUTION: When a ball is thrown into the air, its height depends on the time since the ball was thrown. The equation for its height is h=-t raised to the power 2 + 2t + 3. Find the greatest

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: When a ball is thrown into the air, its height depends on the time since the ball was thrown. The equation for its height is h=-t raised to the power 2 + 2t + 3. Find the greatest      Log On


   

Question 728772: When a ball is thrown into the air, its height depends on the time since the ball was thrown. The equation for its height is h=-t raised to the power 2 + 2t + 3. Find the greatest height attained by the ball.
A. 1 foot
B. 4 feet
C. 5 feet
D. 3 feet
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
h=-t%5E2%2B2t%2B3
h=-t%5E2%2B2t-1%2B1%2B3
h=%28-t%5E2%2B2t-1%29%2B4
h=-%28t%5E2-2t%2B1%29%2B4
h=-%28t-1%29%5E2%2B4
h=-%28t-1%29%5E2%2B4%3C=4 because -%28t-1%29%5E2%3C=0
The greatest height attained by the ball is highlight%28h=4%29

NOTE: The answers give the units as feet.
The problem does not say what the units for h are.
It could not be feet or meters if it was on Earth, because the acceleration of gravity om Earth is 9.8 m/s^2 or 32 ft/s^2.
As a former (substitute) Physics teacher, I am puzzled.
If this happened on planet Earth the equation would be
h=-4.9t%5E2 + ... for h in meters, or
h=-16t%5E2 + ... for h in feet.
The h in the problem is in some fancy alternate units, or else it did not happen on Earth.