Paintball and the Laws of MotionMade by: Andy Hutton and Nick Cupler

Forces are a constant act on us. In sports forces can easily be spotted, whether its kicking a Soccer ball, playing Hockey, passing a Football, etc. There is one sport in particular that i would like to talk about and the forces that make this sport possible. That sport is Paintball. This table will show you some of the forces at work during paintball:
Force
Description
Gravity
Obvious
Drag
Aerodynamic force generated opposite to the direction of the paintballs flight; due to air resistance
Magnus (LIft)
Aerodynamic force generated when a paintball spins
Rotational/Gyroscopic
Several other forces based on the rotational motion (spin) of the paintball coupled with gravitational or drag forces.
Form effect
Aerodynamic force due to seams, splits or other large surface regularities
Wake effect
Aerodynamic force generated by the wake or vortices formed behind a paintball
Centrifugal/Centripetal
Force due to asymmetric fill of a paintball
Sir Isaac Newton, an English physicist and mathematician came up with the idea of gravity and created his famous three laws of motion.
  • Newtons first law: An object at rest stays at rest unless acted on by another force. Also an object in motion stays in motion unless acted on by a force.
This law is a perfect example of how the paintball is forced out of the barrel of the gun. The CO2 hits the paintball released by the bolt making the paintball accelerate out of the barrel at about 300 fps (Feet per second)
external image paintball-bunkered-main_Full.jpg

  • Newtons second law: The acceleration of an object multiplied by the mass of it equals the force produced by the traveling object. (F=ma)
If you take the mass of a paintball and multiply that by the acceleration of it you will have the force exerted when the paintball comes in contact with an object. The average mass of a paintball is about 3.2 grams, and it travels through the air at approximatively 300fps. Do that math... i just know that: Paintball+Skin=Ouch+No break=More paintballs=More ouch... Yes
external image paintball.jpg



  • Newtons third law: Every action force has an equal or opposite reaction force.
The force of the paintball hitting an object (or person) wouldn't have enough momentum to knock you over. When the paintball leaves the barrel it travels through the air and comes hits them. While the paintball was in the air it gained momentum as it accelerated and when it hits the person the momentum gained will be transfered to the person. The subject may stumble if they are off balance but otherwise there wouldn't be enough momentum to push them down. This is just one way to stop a paintball.
Drag and gravity play an important part in stopping a paintball so it doesn't continue off and hit someone in... lets say china. Which wouldn't happen because the ball would just go straight into space but since the earth is a sphere then it would just fly around and hit you in the back. Maybe it would hit some Chinese guy first though, i'm not sure a lot could happen. Ehh don't ya know?
external image simpleTraj.gifBut there needs to be something that will make the paintball continue when it is fired out the barrel and that is the backspin of the ball. When the ball is spinning it has lift making the ball go farther and allows a forward motion in a relatively straight line. If the ball has an imperfection (like a weak spot in the shell of the ball) the ball will go off course when the air flow hits that spot.

Aerodynamics of a paintball with and without back spin:
external image DragEffect.gifexternal image MagnusEffect.gif
YOU ARE A DODO!!! =D
^ I blame Nick ^

Sources:
http://www.forumspile.com/owned/Owned-Paintball.jpg
http://www.infobarrel.com/media/image/389.jpg
http://www.youtube.com/watch?v=jfcsCdZXxKc
http://home.comcast.net/~dyrgcmn/pball/pballIntro.html
http://lennon.csufresno.edu/~nas31/nsa/pballIntro1.html