One Dimensional Projectile Motion Example
Projectile - an object for which the only force acting upon it is gravity. The force of air
resistance is negligibly small or nonexistent for a projectile.

Fg

a y   g  9.8 N
kg
 9.8 m
s2
Uniform Acceleration!
 

v y  voy  gt
  1  
y  yo  v y  voy  t
2
Kinematic Equations
12
 

y  yo  voy t  gt
2
2 2
  
v y  voy  2 g  y  yo 

Notice that all horizontal positions  x  are replaced with


vertical positions  y , and that all accelerati ons a  are

replaced with the Free Fall accelerati on  g  9.8 m 2 

s 
One Dimensional Projectile Motion Example
A minivan falls off of a 221 m tall building.
a. What is its velocity as it hits the ground?
What are
youneed
given?
do you
to know?

vy  ?
 
y  yo  221 m

voy  0

g  9.8 m
s
2
 2 2
  
v y  voy  2 g  y  yo 
2
  
v y  2 g  y  yo 

    
v y   2 g2gy y yoyo 



m
v y   2  9.8
2  221 m 

s 

v y  66 m
s
One Dimensional Projectile Motion Example
A minivan falls off of a 221 m tall building.
b. How long did it stay in the air?
What are
youneed
given?
do you
to know?
t ?
 
y  yo  221 m

voy  0

g  9.8 m
s
2
12
  
y  yo  voy t  gt
2
 
12
y  y o  gt
2
 
2
2 y  yo   gt
 
2 y  yo  2
t

g
One Dimensional Projectile Motion Example
A minivan falls off of a 221 m tall building.
b. How long did it stay in the air?
t ?
 
y  yo  221 m

voy  0

g  9.8 m
s
 
2 y  yo 
t

g
2
2 221 m 
t
 9.8 m
s
2
t  6.7 s