General Physics

Projectile Motion

What is a Projectile?

• Name examples of projectiles.• A projectile has a constant

horizontal velocity.• A projectile has accelerated

vertical motion.

The Horizontal Velocity

• It is constant.• We must again neglect the air

resistance.• There is no other means present to

change the horizontal velocity.

The Vertical Velocity

• This part of the motion is accelerated. By What?

• Gravity!• This part is exactly like Free Fall.

• Vertical speed decreases on the way up• Vertical speed increases on the way down.

Velocity Components

• We have been discussing the components of a projectile’s velocity.

• Why can we separate the velocity into its components?

• Because one does not affect the other.

Independent Velocity Demonstration

• Watch this demonstration.• One ball dropped straight down

while other is simultaneously fired horizontally.

• Which will hit the floor first?• What is the “trick”?• They both fall from rest.

Two-Dimensional Picture

• When the two components are viewed together, the projectile follows a curve.

• What is the name of the curve?• A Parabola.• Check out the video.