Projectiles

Projectiles

Introduction

• In physics, an object that is in free motion under the influence of gravity is referred to as a projectile.
• When we talk about projectiles, we assume there are no significant external forces acting on the object, such as air resistance. However, in real-life scenarios, some objects like sports balls may experience additional forces due to spin, leading to interesting trajectories.

Motion Analysis

• When analysing the motion of projectiles, it's essential to break it down into two main components: vertical and horizontal motion.

Vertical Motion

• Vertical motion refers to the movement of the projectile in the up and down direction, influenced by gravity.
• The key formula for vertical motion is the equation for free fall:
• s = ut + (1/2)gt²
  • s: Vertical displacement (height)
  • u: Initial vertical velocity
  • g: Acceleration due to gravity (approximately 9.81 m/s²)
  • t: Time

Horizontal Motion

• Horizontal motion refers to the movement of the projectile in the left or right direction.
• Unlike vertical motion, there is no acceleration in the horizontal direction (assuming no air resistance).
• The key formula for horizontal motion is:
• d = vt
  • d: Horizontal distance travelled
  • v: Horizontal velocity
  • t: Time

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Projectiles

Independence of Vertical and Horizontal Motion

• A crucial concept in projectile motion is that the vertical and horizontal components of motion are independent of each other.
• This means that the horizontal velocity remains constant throughout the motion, while the vertical velocity changes due to the influence of gravity.

Key Takeaways

• A projectile is any object moving freely under gravity.
• Projectile motion analysis involves considering both vertical and horizontal components of motion.
• Vertical motion is influenced by gravity and described by the equation s = ut + (1/2)gt².
• Horizontal motion occurs at a constant velocity and is described by the equation d = vt.
• Vertical and horizontal motions are independent of each other during projectile motion.

Summary

• Projectiles are objects in free motion under gravity.
• Their motion is analysed by separating it into vertical and horizontal components.
• Vertical motion is influenced by gravity, while horizontal motion occurs at a constant velocity.
• Understanding projectile motion is essential in various fields, such as physics and sports.