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====== Q02. DISCOVER MORE ABOUT PROJECTILES: ======
When a golfer hits a ball, using scientific language,, we call the ball 'a projectile'.

Most people believe that if an object is moving upward and rightward, there must be both an upward and rightward force…. …but they are wrong!

Here are some other types of projectiles..
  * An object dropped from a hand (from rest) is a projectile.
  * An object that is thrown vertically upward is also a projectile. 
  * An object which is thrown upward at an angle to the horizontal is also a projectile:
  
{{:learn:forces:quiz:projectile.gif|}}

We are interested in forces acting AFTER the golf ball (projectile) has been thrown/launched.

  * Link to [[learn:forces:quiz:q02|Q2. HITTING A GOLF BALL - FORCES ON A BALL IN FLIGHT]]
  * Link to [[learn:forces:discover:q02:home|Q2 - DISCOVER: PROJECTILE IDEAS & ACTIVITIES]]

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=== Nerf Gun - Finding the Optimum Range For a Projectile: ===
{{:learn:forces:discover:q02:ideal_projectile_motion_for_different_angles.jpg|
"Ideal projectile motion for different angles" by Cmglee - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons}} [[ http://www3.nd.edu/~tpaulius/nerf_report.pdf|{{ :learn:forces:discover:q02:nerf-gun-tripod.jpg|NERF Gun -Projectiles Launched at an Angle}}]]
  * Setting up a [[http://www3.nd.edu/~tpaulius/nerf_report.pdf|GUI NERF gun controller]]
  * [[https://phet.colorado.edu/sims/projectile-motion/projectile-motion_en.html|PHET Projectile Simulator]]
   * [[http://convertalot.com/ballistic_trajectory_calculator.html|2D Trajectory Calculator]]
  * [[http://hyperphysics.phy-astr.gsu.edu/hbase/traj.html|HyperPhysics Trajectory Calculators]]
  * [[http://www.calctool.org/CALC/phys/newtonian/projectile|Trajectory Calculator (inc. g)]]
  * [[http://www.calculators.org/math/|On-line Maths & Scientific Calculators]]


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====== QUESTIONS - DISCOVER MORE ABOUT PROJECTILES ======
Your mission, should you choose to accept it, is to perform an experiment to find the optimum angle to launch a projectile to gain the maximum range.

First, perform each test using an on-line simulator (see and write down you results).

1. Set up the nerf gun on a table or on a tripod as shown in the image above.
    - Fire the nerf gun horizontally, and at exactly the same time, drop a spare nerf dart over the edge of table or off the barrel of the nerf gun onto the floor.
    - Which nerf dart will hit the ground first - why?

2. Fire one projectile at 60 degrees and another at 30 degrees. Compare the distance (range) that both projectiles travel. What does this indicate? Try some other, similar comparisons

3. If you launch a piano and a tomato at the same angle and with the same speed, which one will go the farthest?

2. We launch three projectiles - one at 40 degrees (a), another at 45 degrees(b) and one at 50 degrees (hint - if you rely on look-up answers from Wikipedia or the table shown above, or similar resources, **you will probably give the wrong answer to this question**):
  - Which projectile travels the farthest overall (the path or 'trajectory' - not the 'range').
  - Which projectile travels the farthest distance ('range' or 'displacement') from the gun:
    - projectile (a)
    - projectile (b)
    - projectile (c)

When you have obtained your results:
  - Create a 'hypopthesis' that you will test in a 'real' experiment.
  - Write down your hypothesis.
  - Perform a 'real-world' test or 'experiment', by setting up a nerf gun on a tripod (as shown above) or on a simple table, and then run a number of trials.

How many trials would be needed for a reliable 'fair' test, and how would you set up this experiment?

=== Additional Questions ===
  - What would be the optimum angle to launch a projectile if gravity were only half as strong?
  - What would be the optimal angle for maximum range if there were no gravity?

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**For more fun, [[events:visiting-alien-day:home|TRY THE 'SAVE THE PLACEBOS CHALLENGE' HERE]]**

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