To determine when the T-shirt reaches its maximum height, we can analyze the given quadratic function:
\[ h(t) = -16t^2 + 72t + 3 \]
Part 1: Time to Reach Maximum Height
The maximum height of a parabola described by the equation \( h(t) = at^2 + bt + c \) occurs at the vertex. The formula for the vertex's x-coordinate (in this case, time \( t \)) is given by:
\[ t = -\frac{b}{2a} \]
Here, \( a = -16 \) and \( b = 72 \):
\[ t = -\frac{72}{2(-16)} = \frac{72}{32} = \frac{9}{4} = 2.25 \text{ seconds} \]
Part 2: Maximum Height
Next, we will use this time to find the maximum height by substituting \( t = 2.25 \) back into the height function \( h(t) \):
\[ h(2.25) = -16(2.25)^2 + 72(2.25) + 3 \]
Calculating \( (2.25)^2 \):
\[ (2.25)^2 = 5.0625 \]
Now substituting back into the height equation:
\[ h(2.25) = -16(5.0625) + 72(2.25) + 3 \]
Calculating each term:
\[ -16(5.0625) = -81 \ 72(2.25) = 162 \]
Now putting everything together:
\[ h(2.25) = -81 + 162 + 3 = 84 \text{ feet} \]
Final Answers
- The T-shirt takes 2.25 seconds to reach its maximum height.
- The T-shirt's maximum height is 84 feet above the field.