Final answer:
The acceleration due to gravity on planet X is approximately 4.0 m/s².
Step-by-step explanation:
The acceleration due to gravity on planet X can be calculated using the equation v² = u² + 2as, where v is the final velocity, u is the initial velocity, a is the acceleration, and s is the distance. In this case, the initial velocity is 0 m/s, the final velocity is 12.0 m/s, and the distance is 14.4 m. Plugging in these values, we get 12.0² = 0² + 2a(14.4). Solving for a, we find that the acceleration due to gravity on planet X is approximately 4.0 m/s².