* No other forces are acting on the object, such as air resistance, friction, or thrust.
* The object is accelerating downwards at a constant rate, known as the acceleration due to gravity (approximately 9.8 m/s² on Earth).
Here's a breakdown of the key concepts:
1. Gravity: The force of attraction between any two objects with mass. In the case of free fall, it's the attraction between the object and the Earth.
2. Acceleration due to gravity (g): The rate at which the velocity of an object in free fall changes. On Earth, g is approximately 9.8 m/s², meaning that the velocity of a falling object increases by 9.8 meters per second every second.
3. Constant velocity: Despite the constant acceleration, objects in free fall can have a constant velocity. This happens when the object has already reached its terminal velocity, where the force of gravity is balanced by the force of air resistance.
4. Zero velocity: An object in free fall can also have zero velocity momentarily. This occurs at the highest point of its trajectory when it changes direction from upward to downward.
5. Upwards motion: Even objects moving upwards can be considered in free fall if the only force acting on them is gravity. This is because they are still accelerating downwards due to gravity, even if their velocity is initially upwards.
Important Points:
* Air resistance is neglected: In the idealized scenario of free fall in Newtonian physics, air resistance is ignored. This is often a reasonable approximation for short distances and dense objects.
* Free fall doesn't necessarily mean falling down: An object can be in free fall even if it's moving upwards, as long as only gravity is acting on it.
Examples of Free Fall:
* A skydiver falling from an airplane before opening their parachute.
* A ball thrown straight up in the air.
* A satellite orbiting the Earth (technically in free fall, but constantly moving in a circular path due to the Earth's gravity).
Free fall is a fundamental concept in Newtonian physics and plays a crucial role in understanding the motion of objects in the presence of gravity.
