Free Fall

Key notes :

Definition of Free Fall:

• Free fall is the motion of an object under the influence of gravitational force only, with no other forces acting on it (e.g., air resistance).

Gravitational Acceleration (g):

• The acceleration due to gravity on Earth is approximately 9.8 m/s² This means the velocity of an object in free fall increases by 9.8 m/s every second.

Neglecting Air Resistance:

• In free fall, air resistance is usually neglected. If air resistance is present, it slows the object down, and the fall is no longer “free.”

Effect of Mass on Free Fall:

• In the absence of air resistance, all objects, regardless of their mass, fall at the same rate. This was famously demonstrated by Galileo at the Leaning Tower of Pisa.

Equations of Motion in Free Fall:

• The equations of motion for uniformly accelerated objects apply to free fall, where the acceleration aaa is replaced by g:

Free Fall from Rest:

• If an object starts from rest (initial velocity u = 0), its speed increases continuously as it falls due to gravity.

Terminal Velocity:

• In real-world situations, an object eventually reaches terminal velocity, where the force of air resistance equals the force of gravity, and the object falls at a constant speed.

Free Fall and Weightlessness:

• During free fall, objects experience apparent weightlessness because there is no support force acting on them.

Examples of Free Fall:

• Dropping a stone from a cliff, a skydiver before opening the parachute (if air resistance is neglected), or astronauts in orbit experiencing microgravity conditions.

Real-World Applications:

• Free fall is studied in designing parachutes, amusement park rides, and space travel, where gravitational effects play a significant role.

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