Year 12 Mechanics Projectile Motion Experiment 3

**Projectile motion exp 1**
**Projectile motion exp 2**
**Projectile motion exp 3**
Find muzzle velocity by firing vertically
Find the muzzle velocity by shooting horizontally
- determine time of flight
- determine muzzle velocity
Find the position the projectile will land, by firing at an angle to the horizontal
- resolve x and y components of velocity
- determine time of flight
- determine horizontal distance.

Purpose:

  • The purpose of this experiment is to determine where to position a projectile will land, when shot from a cannon at an angle from the horizontal.


Equipment

  • Projectile launcher (ME-6801)
  • Stopwatch
  • 1m rulers
  • Bench
  • clamp (can be useful)
  • photo gates (use only for verification as they take a lot of the learning away)

Method:

  • determine the muzzle velocity of the cannon (use experiment 1 or 2 or a reliable photo-gate)
  • Set the cannon to a known angle from the horizontal (use plumb bob to read angle)
projectile_launcher31.jpg
Ensure angle is not so great that the projectile hits the ceiling

  • Resolve the muzzle velocity into its horizontal and vertical components.
projectile_launcher33.jpg projectile_launcher34.jpg
  • Determine the time of flight (calculate to the top of flight then multiply by 2)
projectile_launcher35.jpg
  • Using the time of flight and the calculated horizontal velocity, determine where the landing bucket (I often use a 2L ice-cream container with scrunched up paper and also introduce impulse) needs to be positioned.
projectile_launcher36.jpg

  • Try it out. Students always love to test all this mathematics to see it really mean something in real life :)
projectile_launcher37.jpg


Pitfalls / causes of error

  • The initial vertical height of the cannon should be the same as the landing container (note my ice cream container is on a book)
  • Securing the cannon to the bench (g-clamp or blue-tack etc.) ensures a more accurate shot.

Resources


projectile_motion_applet1.jpg
An excellent projectile motion applet (Java)
projectile_motion_applet2.jpg
Another good animation for projectile motion


Model data:

  • included above and use animation to check values. - it is always fun to change the mass and get students to tell you what will happen.

References / other comments:

  • see Pasco 50 page manual for more info external image pdf.png [[file/view/Pasco_Projectile_Launcher.PDF|Pasco_Projectile_Launcher.PDF]]