Free Fall And Projectile Motion - SS1 Physics Lesson Note

Free Fall:

Free fall refers to the motion of an object under the influence of gravity alone, without any other forces acting upon it. In free fall, objects experience a constant acceleration due to gravity, which is approximately 9.8 m/s² near the Earth's surface. Key characteristics of free fall include:

1. Acceleration: Objects in free fall accelerate downward at a constant rate, typically denoted as "g." The value of g is approximately 9.8 m/s² on Earth, but it can vary slightly depending on the location and altitude. The acceleration due to gravity causes objects to increase their velocity over time.

2. Vertical Motion: In free fall, the object's motion is purely vertical. If the object is initially at rest or thrown vertically upward, it will eventually reach its highest point and then fall back down due to gravity.

3. Independence of Mass: In free fall, the acceleration due to gravity is independent of the mass of the object. All objects, regardless of their mass, will experience the same acceleration and fall at the same rate.

Projectile Motion:

Projectile motion refers to the motion of an object that is launched into the air and then moves along a curved path under the influence of gravity. Key characteristics of projectile motion include:

1. Horizontal Motion: The horizontal component of projectile motion is constant and unaffected by gravity. The object moves horizontally at a constant velocity.

2. Vertical Motion: The vertical component of projectile motion is influenced by gravity. The object follows a parabolic path, experiencing constant downward acceleration due to gravity. As a result, the vertical velocity decreases until reaching its highest point and then increases during the descent.

3. Independence of Horizontal and Vertical Motions: The horizontal and vertical motions of a projectile are independent of each other. The object's horizontal velocity remains constant throughout its flight, while its vertical velocity changes due to gravity.

4. Range and Maximum Height: The range of a projectile refers to the horizontal distance it travels before hitting the ground. The maximum height of a projectile is reached at the peak of its trajectory. Both the range and maximum height depend on the initial velocity, launch angle, and acceleration due to gravity. Adjusting the launch angle can also affect the range. The optimum launch angle for maximum range in the absence of air resistance is 45 degrees. Other factors that can impact the range include air resistance, the height of the launch point, and the presence of external forces.

Understanding free fall and projectile motion is essential in various fields, such as physics, engineering, sports, and ballistics. These concepts allow us to analyse and predict the motion of objects in free fall and the behaviour of projectiles launched at different angles and velocities.