PhysicsPhysicsProjectile MotionProjectile Motion

What happens to an object when it What happens to an object when it has combined horizontal and has combined horizontal and

vertical motion?vertical motion?

Reach out an touch someone at 30 to 40 km range (18-24 miles).

What is a ProjectileWhat is a Projectile

Any object which is in motion that is Any object which is in motion that is subject to the effects of gravitational subject to the effects of gravitational acceleration, g.acceleration, g.

Typically such an object is thrown or Typically such an object is thrown or launched.launched.

Examples:Examples:Football, Rock, Basketball, Football, Rock, Basketball, People.People.

Turn Your Attention To Turn Your Attention To The RearThe Rear

Vertical and Horizontal Vertical and Horizontal MotionMotion

When vertical and horizontal motion When vertical and horizontal motion combine an object will travel along a combine an object will travel along a curved path.curved path.

This path follows the general shape of This path follows the general shape of a parabola.a parabola.

It is called a ballistic arc.It is called a ballistic arc.

Horizontal ComponentHorizontal Component

As we saw with the cart, it moved at a As we saw with the cart, it moved at a constant velocity in the horizontal.constant velocity in the horizontal.

This is called the “Inertial This is called the “Inertial Component.”Component.”

(More about inertia at a later date).(More about inertia at a later date).

We label it on the picture diagram as We label it on the picture diagram as

vvxx

Vertical ComponentVertical Component

The vertical component is subject to The vertical component is subject to Earth’s gravity, g.Earth’s gravity, g.

As such the object goes faster the As such the object goes faster the longer and/or farther it falls.longer and/or farther it falls.

This is called the gravitational This is called the gravitational component and we label on the component and we label on the

diagram as diagram as vvyy..

Adding The Two MotionsAdding The Two Motions

But Why Does It Curve?But Why Does It Curve?The Horizontal & Vertical Are Independent Of The Horizontal & Vertical Are Independent Of

Each Other!!!Each Other!!!

Notice Anything?Notice Anything?

The x and y components add to create The x and y components add to create the objects total velocity. (Note that the objects total velocity. (Note that vvxx doesn’t change). doesn’t change).

If They Add To Form The If They Add To Form The Motion..Motion..

Then a velocity applied at an angle Then a velocity applied at an angle can be broken apart into two pieces, can be broken apart into two pieces, vvxx and v and vy.y.

100 m/s

30°86 m/s

50 m/s

Once The Launch Vector Is Once The Launch Vector Is In Two Pieces …..In Two Pieces …..

We can figure out range of the We can figure out range of the projectile.projectile.

Height that it will fly.Height that it will fly.

How long it will be airborne.How long it will be airborne.

HANG TIME IS THE KEY TO HANG TIME IS THE KEY TO PROJECTILE MOTION PROJECTILE MOTION PROBLEMS!!!!!!!PROBLEMS!!!!!!!

Handy WebsitesHandy Websites

This lecture is taken from the website for This lecture is taken from the website for your text.your text.

http://www.physicsclassroom.com/Class/vechttp://www.physicsclassroom.com/Class/vectors/U3L2a.htmltors/U3L2a.html

I also recommend….I also recommend….

http://www.phschool.com/science/cpsurf/mehttp://www.phschool.com/science/cpsurf/mechanics/1_3lear.htmlchanics/1_3lear.html

http://lectureonline.cl.msu.edu/~mmp/http://lectureonline.cl.msu.edu/~mmp/kap3/cd060.htmkap3/cd060.htm