What is Projectile Motion?

Instructional Objectives: Students will be able to: Define Projectile Motion Distinguish between the different types of projectile motion Apply the concept to a toy car and measure its velocity

Define these terms: Components of a vector Projectile Projectile motion Resolution Resultant Scalar Vector

Projectile Motion Two-dimensional motion of an object Vertical Horizontal

Examples: Ball being thrown, water coming out of the hose, a bullet fired from a gun, arrow shot from a bow, cannonballs, fountains.

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 Bullet!

Examples of Projectile Motion Launching a Cannon ball

RANGE is the horizontal displacement of the projectile (x) MAXIMUM HEIGHT is the vertical displacement of the projectile (y)

Question At the highest point what can be said about the vertical velocity?

GRAVITY FREE ENVIRONMENT

THROWN OVERHEAD ( W/ GRAVITY)

THROW AT THE MONKEY (FAST) WITH GRAVITY ON

THROW AT THE MONKEY (SLOW) WITH GRAVITY ON

THE PLANE AND THE PACKAGE

THE TRUCK AND THE BALL

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

Types of problems The problems we do break down to four basic types Find the time to hit the ground. Find the range (displacement in the x direction) Find the maximum Height Find the initial velocity (with or without angle)

REMEMBER: 1. the horizontal velocity of a projectile is constant (never changing in value), 2. there is uniform vertical acceleration caused by gravity; its value is 9.8 m/s2 3. the vertical velocity of a projectile changes by ~10 m/s each second, the horizontal motion of a projectile is independent of its vertical motion.

Horizontal Motion A cannon is on the top of a 100 m high hill. If the cannon shoots a cannonball at 50 m/s. What is the distance that the cannonball will travel?

Horizontal Motion 2 A baseball rolls off of a table that is 1.5 meters tall. If the baseball hits the ground 1 meter away from the table how fast was it going when it rolled off?

Horizontal Motion 3 The same baseball from the previous problem keeps rolling down the hall at the same speed. It rolls over the top of a ledge and hits the ground 3 meters from the ledge. How tall is the ledge?

Factors Affecting Projectile Motion What two factors would affect projectile motion? Angle Initial velocity Initial Velocity Angle

Class Exercise An object is fired from the ground at 100 meters per second at an angle of 30 degrees with the horizontal Calculate the horizontal and vertical components of the initial velocity After 2.0 seconds, how far has the object traveled in the horizontal direction? How high is the object at this point?

Solution Part a Part b Part c

What is projectile motion? Final Thoughts What is projectile motion?