2-D Projectile Motion

Physics

Chapter 3 Section 3

Pages 98-105

2-Dimensional Projectile Motion• Motion of objects moving in 2 dimensions which

are under the influence of gravity.

Projectiles • Objects thrown or launched into the air and

whose motion is subject to gravity’s pull

• Projectile motion is essentially free fall motion with an initial horizontal velocity OR initial horizontal and vertical velocity.

Launched at an angle

Launched horizontally

Projectiles follow a parabolic path

2 Types of Projectile Motion1. Projectiles launched horizontally

NO initial upward or downward motion

All motion will be horizontal (x) and down (y)

Equations for horizontally launched projectilesHorizontal Motion

Δx = VxΔtVx = Vxi = constant

Vertical MotionΔy = +½ g •(Δt)2

Vyf = +g •ΔtVyf

2 = +2g •Δy

Overall Final Velocity Vf

2 = Vx2 + Vyf

2

2 Types of Projectile Motion2. Projectiles launched at an angle Use x and y components to analyze motion Have initial upward angle of motion (could be initially downward as well) Have initial horizontal motion

Physics is all around you…Physics is PHUN!

• You can find Physics in a baseball stadium (At Fenway Park)

• I bet you never thought that Physics was a major part of baseball stadium design.

Physics is all around you…Physics is fun!

• What makes THE GREEN MONSTER so different from other baseball stadium outfield walls?

• Why the answer is simple…..Physics!

• The Green Monster

Equations for Projectiles Launched at an Angle Δx = Vi (cosθ) •Δt

Vxi = Vi (cosθ) remains constant

Vyi = Vi(sinθ)

Δy = Vi(sinθ) • Δt + ½ g •(Δt)2

Vyf = Vi(sinθ) + g •(Δt)

Vyf2 = Vi

2(sinθ)2 + 2g •(Δy)

Overall Final Velocity

Vf2 = Vx

2 + Vyf2

Substitution of equationsThere will be times when you do not have the values

you need, but you have almost enough. During those times, you can rearrange equations to substitute variables.

This is the easiest equation to rearrange, but others work as well.

Δx = Vi (cosθ) •Δt

Δx = Vi

(cosθ) •Δt

Projectile Motion Internet Link:

Projectile Motion Page from "The Physics Classroom“

Physics Projectile Webquest

Firing

Ball

Golf #1

Golf #2

Monkey

Cannon