1. Projectile Motion
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Physics

2. Projectile Motion What is a Projectile Motion?
Any object that continues in motion and is influenced only by gravity
an object thrown straight upward is a projectile
an object thrown upward at an angle to the horizontal
an object dropped from rest is a projectile

3. Vertical Direction (aka. Free Fall)

4. Vertical and Horizontal Motion
Vertical Motion
Velocity = Vx
Displacement = Δx
Velocity = Vy
Displacement = Δy
Vx is always constant
Gravity acts vertically,
a = -9.8 m/s2

5. t=0.247 s Practice Problem vix=72.9 m/s vix=? m/s viy= 0 m/s
A basketball rolls across a 18.0 m pitch. The ball drops 0.3 m from the edge. Determine the ball’s speed? How long did it take to roll over the pitch?
vix=? m/s
viy= 0 m/s
t=0.247 s
t=? s
t=0.247 s
vix=72.9 m/s

6. Simplified Projectile Equation
Horizontal Motion
Vertical Motion

7. Cliff example
A boulder rolls off of a cliff and lands seconds later 68 m from the base of the cliff.
What is the height of the cliff?
Δy= ? a=-9.81 m/s2
t = 6.39 s Vx=?
Vy,i = 0 Δx= 68 m

8. Problem (Con.)
What is the velocity of the boulder just as it strikes the ground?
The boulder rolls off the cliff horizontally
Therefore, we are looking for Vx

9. Projectile Motion Review
Horizontal Components
Vertical Components
Horizontal Velocity is constant throughout the flight
Horizontal acceleration is 0
Initial vertical velocity is 0
Vertical acceleration is constant: m/s2