Answer:
B
Step-by-step explanation:
Answer: 9
Step-by-step explanation: process of elimination
Answer:
After 3 seconds
Step-by-step explanation:
Given

Required
Seconds to attain maximum height
The maximum of a quadratic function
is calculated using:

So, we have:

Where:
and 
So:


Cancel out negatives


Answer:
1) 3, 4
2) . 1, 2, 3, 4, 5, 6
3) 5, 6
4) . 1, 2, 5, 6
Step-by-step explanation: