$$d = \frac{1}{2}gt^2$$
where:
* d is the distance the object falls (in this case, 144 ft)
* g is the acceleration due to gravity (in this case, 32 ft/s²)
* t is the time taken for the object to fall
Substituting the given values into the equation, we get:
$$144 = \frac{1}{2}(32)t^2$$
Solving for t, we get:
$$t^2 = \frac{144}{16}$$
$$t^2 = 9$$
$$t = \sqrt{9}$$
$$t = 3 \text{ seconds}$$
Therefore, it takes the rock 3 seconds to reach the ground.
