Answer:
a.
b.
Step-by-step explanation:
You have the following formula given in the exercise:
a. If the object is 50 feet above the ground, you can identify that the value of the variable "h" would be the following:
Then, knowing that value, you can substitute it into the given formula and then evaluate in order to calculate the time in seconds for the object to be 50 feet above the ground.
This is:
b. When the object reaches the ground, the value of "h" is:
Therefore, substituting this value into the formula and evaluating, you get that time (in seconds) it takes to the object reaches the ground is: