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โšพ๏ธHonors Physics Unit 5 Review

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5.3 Projectile Motion

โšพ๏ธHonors Physics
Unit 5 Review

5.3 Projectile Motion

Written by the Fiveable Content Team โ€ข Last updated September 2025
Written by the Fiveable Content Team โ€ข Last updated September 2025
โšพ๏ธHonors Physics
Unit & Topic Study Guides

Projectile motion is all about objects flying through the air. It's like throwing a ball, but with math! We'll look at how things move in arcs and why they follow those paths.

Knowing projectile motion helps us understand everything from sports to space travel. We'll learn how to predict where things will land and how high they'll go, using some cool equations and concepts.

Projectile Motion

Properties of projectile motion

  • Projectile motion describes the movement of an object launched into the air at an angle (projectile)
    • The curved path followed by the projectile is its trajectory
      • In the absence of air resistance, the trajectory forms a parabolic shape
  • Horizontal and vertical components of projectile motion can be analyzed independently
    • Horizontal velocity remains constant throughout the motion (assuming no air resistance)
      • No acceleration acts in the horizontal direction
    • Vertical velocity changes due to the constant downward acceleration of gravity ($g = 9.81 m/s^2$)
  • The time of flight is the same for both horizontal and vertical components of motion
  • Initial velocity (magnitude and direction) determines the projectile's trajectory

Calculations with kinematic equations

  • Kinematic equations allow calculation of various aspects of projectile motion
    • Horizontal displacement: $x = v_0 \cos(\theta) t$
      • $v_0$ = initial velocity, $\theta$ = launch angle, $t$ = time of flight
    • Vertical displacement: $y = v_0 \sin(\theta) t - \frac{1}{2}gt^2$
      • $g$ = acceleration due to gravity
  • Vector analysis resolves initial velocity into horizontal and vertical components
    • Horizontal component: $v_{0x} = v_0 \cos(\theta)$
    • Vertical component: $v_{0y} = v_0 \sin(\theta)$
    • Position and velocity at any time found by treating components independently

Range and height of projectiles

  • Range is the horizontal distance traveled by a projectile before hitting the ground
    • Range formula: $R = \frac{v_0^2 \sin(2\theta)}{g}$
      • Maximum range occurs at a launch angle of 45ยฐ
  • Maximum height is the highest vertical distance reached during the projectile's flight
    • Maximum height formula: $h_{max} = \frac{v_0^2 \sin^2(\theta)}{2g}$
    • Maximum height occurs at half the total time of flight
      • Time to reach maximum height: $t_{max} = \frac{v_0 \sin(\theta)}{g}$
  • Symmetry in projectile motion: The path of ascent mirrors the path of descent in ideal conditions

Fundamental principles and applications

  • Newton's laws of motion govern projectile motion, explaining the forces and accelerations involved
  • Air resistance affects real-world projectile motion, causing deviations from ideal parabolic trajectories
  • Ballistics, the study of projectile motion, has applications in various fields including sports, military, and forensics