Final answer:
The total energy of the ball-Earth system when the ball hits the ground is 66 J.
Step-by-step explanation:
The total energy of a system consisting of a ball thrown from the top of a cliff on Earth, when the ball hits the ground, is the sum of its kinetic energy and gravitational potential energy.
In this case, the initial kinetic energy of the ball is 16 J, and the initial gravitational potential energy is 50 J.
Therefore, the total energy of the ball-Earth system when the ball hits the ground is 16 J + 50 J = 66 J.