Uniform Motion
* Definition: Motion where an object travels at a constant speed in a straight line.
* In Free Fall: This is rarely the case in real-world free fall. The only way an object could fall uniformly is if there were absolutely no air resistance and gravity acted consistently throughout the fall.
Non-Uniform Motion
* Definition: Motion where an object's speed or direction changes over time.
* In Free Fall: This is the typical scenario. Here's why:
* Air Resistance: As an object falls, it encounters air resistance (friction from the air). This force opposes the object's motion, causing it to slow down. The faster the object falls, the greater the air resistance.
* Gravity: While gravity is a constant force, it's not uniform across the Earth. As an object falls, it gets closer to the Earth's center, slightly increasing the force of gravity. This effect is usually small but noticeable over significant distances.
Key Points
* Terminal Velocity: As an object falls, it eventually reaches a point where air resistance equals the force of gravity. At this point, the object stops accelerating and falls at a constant speed called terminal velocity.
* Idealized Scenarios: In physics problems, we often simplify free fall by ignoring air resistance to make calculations easier. This gives us a model of uniform acceleration due to gravity.
In Summary
Free fall is almost always non-uniform due to air resistance. While gravity is a constant force, air resistance changes with speed, making the overall motion non-uniform. However, in theoretical scenarios where air resistance is negligible, free fall can be considered uniform.
