Answer:
Model:

The dog land on the ground after 0.8706 seconds.
Explanation:
The model that said the height of the dog above the ground is a model of uniform acceleration motion, so it is:

Where
is the initial height,
is the initial velocity and
is the gravity.
So, replacing
by zero,
by 14 feet per second and
by
, we get that the model for the height of the dog above the ground is:

Then, the time t when the dog land on the ground is calculated replacing
by zero and solving for t as:

Now, we have two possible solutions:
or

Taking into account that t=0 is the time when the dog leaps into air, the time when the dog land on the ground is equal to 0.8706 seconds and it is calculated as:
