Here is an image displaying the correct answers.
Answer:
d) v1 = v2 = v3
Explanation:
This can be determined through the principle of energy conservation. We assess the total mechanical energy E=K+U (the sum of kinetic energy and gravitational potential energy) at both the initial and final positions, ensuring they remain constant.
<pInitially, for the three spheres, we have:

Finally, for the three spheres, we see:

<pGiven that

, and since

remains identical for all spheres, it follows that

is identical for all spheres, indicating that

, the final velocity, is equal for each ball.
For this issue, the answer is clarified as the system takes in energy (+). The surroundings contribute 84 KJ of work. Whenever a system is receiving work from its surroundings, the value will be positive. Therefore, it sums to 12.4 KJ + 4.2 = 16.6 KJ.