9514 1404 393
Answer:
4.0 seconds
Explanation:
The equation for ballistic motion is ...
y = -4.9t^2 +22.1t
We want to find the larger value of t that makes y = 10.
10 = -4.9t^2 +22.1t
4.9t^2 -22.1t +10 = 0
Using the quadratic formula, we have ...
t = (22.1 + √(22.1² -4(4.9)(10)))/(2·4.9) = (22.1 +√292.41)/9.8 = 39.2/9.8
t = 4
The ball was in the air 4 seconds before it got stuck.