* Ideal Free Fall: In a perfect vacuum with no air resistance, an object in free fall experiences a constant acceleration due to gravity. This acceleration is approximately 9.8 m/s² on Earth. So, its speed keeps increasing at a steady rate.
* Real-World Free Fall: In reality, air resistance plays a significant role. As an object falls, it encounters air resistance which opposes its motion. This force increases with the object's speed.
* Initial Stage: At the beginning of the fall, the object's speed is low, and air resistance is negligible. Therefore, the acceleration is close to 9.8 m/s².
* Terminal Velocity: As the object accelerates, air resistance increases until it balances the force of gravity. At this point, the object reaches its terminal velocity, and its acceleration becomes zero.
Therefore:
* An object in free fall in a vacuum experiences a constant acceleration.
* An object in free fall in air experiences an increasing acceleration initially, but it eventually reaches a terminal velocity where its acceleration becomes zero.
