Bennett Mechanical Comprehension Practice Test 2026 - Free Practice Questions and Review Guide

During a ballistic trajectory, the quantity that remains constant is acceleration. When an object is in free fall or moving through a vacuum, the only force acting on it (assuming air resistance is negligible) is gravity. This results in a constant acceleration downwards. In most cases on Earth, this acceleration due to gravity is approximately 9.81 m/s².

While distance, velocity, and time can vary throughout the trajectory, acceleration remains unchanged as the object moves through the gravitational field. This understanding is crucial in the context of projectile motion, where the only variable affecting the object's path is gravitational acceleration, leading to predictable motion patterns.