(i) Free Fall:
– Definition: Free fall refers to the motion of an object under the sole influence of gravity, where the only force acting on the object is gravity itself. In free fall, the object is subject to acceleration due to gravity, and it falls without any other forces, such as air resistance, acting upon it.
– Characteristics: During free fall, all objects near the surface of the Earth experience the same acceleration due to gravity (approximately 9.81 m/s²), regardless of their mass. This means that in the absence of other forces, all objects fall at the same rate.
(ii) Acceleration Due to Gravity:
– Definition: Acceleration due to gravity, often denoted as “g,” is the acceleration experienced by an object when it is in free fall near the surface of a celestial body, such as Earth. On Earth, the standard value for gravitational acceleration is approximately 9.81 meters per second squared (m/s²).
– Characteristics: Gravitational acceleration represents how quickly an object’s velocity changes under the influence of gravity. It determines the rate at which objects fall when dropped from a height.
(iii) Escape Velocity:
– Definition: Escape velocity is the minimum velocity an object must attain to break free from the gravitational pull of a celestial body (e.g., a planet or moon) and move into space without being pulled back. It is the speed required for an object to escape the gravitational field entirely.
– Calculation: The escape velocity depends on the mass and radius of the celestial body. The formula to calculate escape velocity (Ve) is: Ve = √(2 * G * M / R), where G is the gravitational constant, M is the mass of the celestial body, and R is its radius.
(iv) Centripetal Force:
– Definition: Centripetal force is the force that acts on an object moving in a circular path, directing it toward the center of the circle. It is responsible for keeping an object in circular motion and preventing it from moving in a straight line tangent to the circle.
– Characteristics: The magnitude of the centripetal force depends on the mass of the object, its speed, and the radius of the circular path. Mathematically, the centripetal force (Fc) is given by Fc = (m * v²) / r, where m is the mass of the object, v is its velocity, and r is the radius of the circular path.
In summary :
– Free fall is the motion of an object under the sole influence of gravity.
– Acceleration due to gravity (g) is the rate at which objects accelerate when in free fall near the surface of a celestial body.
– Escape velocity is the minimum velocity required for an object to break free from a celestial body’s gravitational pull.
– Centripetal force is the force that keeps an object moving in a circular path and directs it toward the center of that path.