1. What is Projectile Motion?

2. Instructional Objectives:
Students will be able to:
Define Projectile Motion
Define Trajectory
Characteristics of a projectile's motion
Horizontal and vertical components of velocity and displacement
Initial velocity components
Examples of problems

3. Projectile Motion
A projectile is an object upon which the only force acting is gravity. A projectile is any object which once projected or dropped continues in motion by its own inertia and is influenced only by the downward force of gravity (neglecting air resistance).
A trajectory is the path followed by a projectile. The shape is a parabolic curve.
-Its path is determined by gravitational acceleration.
The motion is in two-dimensions
Vertical
Horizontal

4. Types of Projectile Motion
Horizontal
Motion of a ball rolling freely along a level surface
Horizontal velocity is ALWAYS constant
Vertical
Motion of a freely falling object
Force due to gravity
Vertical component of velocity changes with time
Parabolic
Path traced by an object accelerating only in the vertical direction while moving at constant horizontal velocity

5. Examples of Projectile Motion
Launching a Cannon ball

7. Horizontal Projectile

8. Equations
X- Component
Y- Component
Vectors
Note: g= 9.8 m/s^2

9. Class Exercise
A ball is projected horizontally from the edge of a table that is 0.862m high, and it strikes the floor at a point 1.42m from the base of the table.
The acceleration of gravity is 9.8m/s2.
What is the initial speed of the ball?

10. Explanation:
Choosing the edge of the table as the origin of our coordinate system, we have
y= viy(t) - 1/2g(t)2
With viy = 0 so that
y=-1/2g(t)2

11. Class Exercise Cont’d
A toy car runs off the edge of a table that is m high. The car lands m from the base of the table.
How long does it take for the car to fall?
The acceleration due to gravity is 9.8 m/s2.
What is the horizontal velocity of the car?

12. Summary
Projectiles travel with a parabolic trajectory due to the influence of gravity,
There are no horizontal forces acting upon projectiles and thus no horizontal acceleration,
The horizontal velocity of a projectile is constant (a never changing value),
There is a vertical acceleration caused by gravity; its value is 9.8 m/s/s, down,
The vertical projectile is any object upon which the only force is gravity,
Vertical velocity of a projectile changes by 9.8 m/s each second,
The horizontal motion of a projectile is independent of its vertical motion.

13. Practice TIME!!!