Echoes Within

🌍 Free Fall

🔹 Introduction

When an object falls toward the Earth under the influence of gravity alone, without any other external force (like air resistance, push, or pull), the motion is called free fall.

In free fall, the only force acting on the body is the force of gravity. This makes the object accelerate toward the center of the Earth with an acceleration equal to the acceleration due to gravity (g = 9.8 m/s²).

🔹 Characteristics of Free Fall

1. The object experiences uniform acceleration due to gravity.

2. The acceleration is always directed downward, toward the Earth’s center.

3. The mass of the falling object does not affect the acceleration (ignoring air resistance).

   • Example: A stone and a feather would fall with the same acceleration in a vacuum.

🔹 Equations of Motion in Free Fall

The equations of motion can be applied to free-falling bodies by replacing acceleration $a$ with $g$.

1. Velocity after time $t$:

   v=gt

2. Distance covered in time $t$:

   s=1/2gt2

3. Velocity before hitting the ground from height $h$:

   v=Sq. root of (2gh)​

🔹 Example

If a stone is dropped from a tower of height 20 m, find the time it takes to reach the ground.

s=1/2gt2

20=12×9.8×t2

 t2=20/4.9≈4.08

 t≈2.02 seconds

So, the stone will take about 2 seconds to reach the ground.

🔹 Important Note

• In real life, air resistance affects free fall. For example, a feather falls slower than a stone.

• But in a vacuum (absence of air), all objects fall at the same rate regardless of their mass.

✅ Conclusion:
Free fall is the motion of a body when gravity is the only force acting on it. It helps us understand the role of gravitational acceleration in determining the speed and time of falling objects.