Free fall

Definition

Free fall is the motion of a body where gravity is the only force acting upon it. In this state, all objects, regardless of their mass, experience the same acceleration due to gravity, which is approximately $$9.81 \, m/s^2$$ near the Earth's surface. This concept illustrates the uniformity of gravitational influence and connects deeply with Newtonian physics and gravitation principles.

5 Must Know Facts For Your Next Test

1. In free fall, all objects fall at the same rate regardless of their mass, demonstrating that gravitational acceleration is uniform.
2. Free fall occurs only when air resistance is negligible; otherwise, terminal velocity will be reached.
3. On the Moon, free fall still occurs, but the acceleration due to gravity is only about $$1.62 \, m/s^2$$, resulting in slower falls compared to Earth.
4. The concept of free fall was significantly advanced by Galileo, who conducted experiments demonstrating that objects dropped from the same height hit the ground simultaneously.
5. In free fall, an object will continue to accelerate until it encounters resistance or reaches terminal velocity.

Review Questions

• How does free fall illustrate Newton's laws of motion, particularly in relation to acceleration?
  • Free fall perfectly exemplifies Newton's Second Law, which states that acceleration is a result of force. In this case, gravity is the sole force acting on an object in free fall, resulting in a consistent acceleration of approximately $$9.81 \, m/s^2$$ towards the Earth. The mass of the object does not affect this acceleration; both light and heavy objects will fall at the same rate if air resistance is negligible.
• Discuss the impact of air resistance on free fall and how it relates to the concept of terminal velocity.
  • Air resistance plays a critical role in determining how objects behave when they are in free fall. As an object falls, it accelerates until the upward force of air resistance equals the downward gravitational force. At this point, it stops accelerating and continues to fall at a constant speed known as terminal velocity. This demonstrates that while free fall assumes no air resistance, real-world conditions require consideration of this factor for accurate predictions.
• Evaluate how Galileo's experiments on free fall challenged existing beliefs about motion and set the stage for modern physics.
  • Galileo's experiments on free fall were revolutionary as they challenged the Aristotelian belief that heavier objects fall faster than lighter ones. By demonstrating that all objects accelerate equally under gravity in a vacuum, he laid down foundational concepts for Newton's laws of motion. His work emphasized empirical evidence and experimentation over philosophical reasoning, ultimately paving the way for modern physics by shifting the understanding of motion from qualitative observations to quantitative analysis based on gravity's consistent effects.

Related terms

Acceleration due to gravity: The rate at which an object accelerates towards the Earth when in free fall, usually denoted as $$g$$ and approximately equal to $$9.81 \, m/s^2$$.

Newton's Second Law: A fundamental principle stating that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass, expressed as $$F = ma$$.

Terminal velocity: The constant speed that a freely falling object eventually reaches when the resistance of the medium prevents further acceleration.