Projectile Motion

1
Projectile Motion

• By Sam, Jacob, and Wendell

2
Outline

• Drag (air resistance)
• How does air density affect trajectory
• How does wind affect affect trajectory
• Model of a cannon in 3 dimensions (java)

3
Recap

• Shoot a projectile at a target
• Time step is .01 seconds
• Optimal angle 45

4
How drag works

• Drag cd r V2/2 A
• Drag coefficient (cd) is a constant on earth
• Density of the air ( r ) changes with altitude
• Velocity of the cannon ball (V2) starts between
  400 and 500 m/s
• Surface area of the cannon ball (A) is 0.04524 m2
  

5
3D plot

• Added Z axis
• Used two graphs to get 3D
• Wind in two directions
• New angle (Z)
• Y,X
  X,Z

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Density change

• Higher altitude less density No change
  in density

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Wind

• No wind on the Y axis
• Wind factors into drag

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No wind

• wind increases drag no wind gives the
• - pushes the ball ball a natural
  path
• a
  graph with no wind

9
Results

• Wind has little effect on trajectory of a cannon
  ball
• Density change can make a cannon ball go farther
• Adding the Z axis made it much harder to hit the
  target

10
References

• http//www.grc.nasa.gov/WWW/K-12/airplane/falling.
  html
• http//www.nps.gov/fomc/archeology/cannon.jpg
• http//orgs.unt.edu/talons/rush/cannon.jpg