Projectile Motion
What is projectile motion?

Projectile motion is the motion of an object
thrown or projected into the air, subject to
only the acceleration of gravity. The object is
called a projectile, and its path is called
its trajectory.
Free Fall and Projectile I

When an object is thrown horizontally, will it
reach the ground at the same time with a
freely falling object?

Can an object launched horizontally be
considered as a freely falling object?
A projectile moves horizontally with constant velocity
while being accelerated vertically. The result is a motion
in a curved path.
An object projected
horizontally will
reach the ground in
the same time as
an object dropped
vertically.
No matter how
large the horizontal
velocity is, the
downward pull of
gravity is always
the same.
The cannonball falls the same amount of distance as it did
when it was merely dropped from rest
Horizontally Launched Projectiles
Projectiles which have NO upward trajectory and NO initial
VERTICAL velocity.
vox  vx  constant
voy  0 m / s
Projectile Motion 1 Formula

Projectile Motion 1 Formula


A ball is thrown horizontally from a window
that is 30 m high with a velocity of 12 m/s.
Find:
a.
b.
c.
How long will it take for the ball to reach the
ground;
How far from the building will it land;
How fast will the ball hit the ground.
A stone is thrown horizontally at a speed of 5.0 m/s from
the top of a cliff 78.4 m high.
a. How long does it take the stone to reach
the bottom of the cliff?
b. How far from the base of the cliff does
the stone strike the ground?
c. What are the horizontal and vertical
components of the velocity of the stone
as it hits the ground?
You Try!!!
2. Freddie Frog takes a swan
dive from a board which is
13 meters from the surface
of the water. He leaves the
board at 6.5m/s. If his
initial velocity is horizontal,
at :
(a) what time will he hit
the surface of the
water
(b) how far is Freddie
from the dropping
point?
(c) what speed will
Freddie hit the water.
A steel ball rolls with constant velocity on a table top
0.950 m high. It rolls off and hits the ground 0.352 m
from the edge of the table. How fast was the ball
rolling?
A beach ball, moving with a speed of 1.27 m/s, rolls off a
pier and hits the water 0.75 m from the pillar of the pier.
How high is the pier above the water? What is the initial
velocity of the ball in the y direction?
A ball rolls off of a table with a speed of 3.2 m/s. The
table is 1.5 m high.
a. When does the ball hit the ground?
b. How far away from the base of the table does
the ball travel?
c. With what speed does the ball hit the floor?
Projectiles move in TWO dimensions
Since a projectile
moves in 2dimensions, it
therefore has 2
components just
like a resultant
vector.
 Horizontal and
Vertical