Question

A boy throws a baseball across a field. The ball reaches its maximum height, 18 meters, after 1 second. After approximately 2.3 seconds, the ball lands on the ground. The ball’s motion can be modeled using the function f(x) = –10x2 + 20x + 8. What is the height of the ball 1.5 seconds after it is thrown? A. 11.7 meters B. 13.8 meters C. 15.5 meters D. 17.5 meters

Answer 1

option C 15.5meters

Explanation:

Just did the test and got 100%

Answer 2

Since the ball will reach the maximum height of 18 meters after 1 second, meaning after 1 second it will start to go down. So will expect that the height will be lower than 18 m after 1.5 s.
f(x) = –10x2 + 20x + 8
f(x) = –10(1.5^2) + 20(1.5) + 8
f(x) = 15.5 m