The function is 
, and according to the description of the function in the problem statement, we have the following:
at t=0 after being thrown (that is, at initial time), the height of the ball is calculated by h(0) as follows:
(ft), which is the initial height, as expected.
At t=1 (sec), the height would be
.
etc.
The path is parabolic, as we know by seeing that the function is a quadratic polynomial function. This function has been given in factored form as well. From that we can see that the zeros of the function are t=7 and t=-2.
This means that at t=7 sec, the height h is 0, which means that the ball has hit the ground. t=-2 has no significance in the context of our problem so we just neglect it.
Answer: B) 7 sec
at t=0 after being thrown (that is, at initial time), the height of the ball is calculated by h(0) as follows:
At t=1 (sec), the height would be
etc.
The path is parabolic, as we know by seeing that the function is a quadratic polynomial function. This function has been given in factored form as well. From that we can see that the zeros of the function are t=7 and t=-2.
This means that at t=7 sec, the height h is 0, which means that the ball has hit the ground. t=-2 has no significance in the context of our problem so we just neglect it.
Answer: B) 7 sec