HEL The height, h (in feet), of a golf ball depends on the time, t (in seconds), it has been in the air. Sarah hits a shot off the tee that has a height modeled by the velocity function -16t2+80t=h(t).

a. When does the ball hit the ground? Show work to justify your answer.

b. Describe the graph of the function by answering the questions in wordsWhat shape is the graph (and how do you know)?

How does it open (and how do you know)?

Does the graph have arrows (and how do you know)?

What is the y-intercept (and how do you know)?