Instructions

1. See the lab example and template at the bottom of this page for how to write up the lab report.
2. Click on the PhET simulations from the University of Colorado on projectile motion https://phet.colorado.edu/sims/html/projectile-motion/latest/projectile-motion_en.html (Links to an external site.)
3. Explore and play with the simulation to see how all the features work.
4. Go to the intro mode
   • Put the cursor in the middle of the Cannon and drag it down so it is at zero altitude
   • Leave the initial speed at the default value of 15 m/s
   • Tilt the Cannon to 90 and fire
   • Now tilt the cannon to the following values and observe the tracks 80,70,60 ,50,45,30,
   • Which angle had the largest range? Put that in your discussion section
5. Go to the vectors mode
   • Repeat again the angles as in step three but set the do it twice. Once with air resistance and once without.
   • Turn off air resistance
   • Set the speed to slow.
   • Set the radio button to components and check off velocity, acceleration, and force vectors.
   • Observe how the velocity in the x direction does not change whereas the velocity in the y direction does. This is because there is no force in the x direction so there is NO corresponding acceleration.
   • Observe how the velocity in the y direction does change. Precisely because there is a force acting in that direction causing it to change.
6. Set the mode to drag
   • Set the angle the 45
   • Set the drag coefficient to .10
   • Repeat the firing for drag coefficients for .20,.30,.40,….,80,.90
   • Is the distance the cannon ball lands directly or indirectly proportional to the drag coefficient? This carefully about the words as you make your decision. Put that in your discussion section
7. Set the mode to lab
   • Set the angle to 45
   • Set the air resistance to on
   • Set the diameter to .10m and fire
   • Repeat for diameters .20m, .30m ….1.00 m
   • Is the distance fired in this case directly or indirectly proportional to the diameter? Answer in the discussion section.
8. Monkey Problem
   • There is a beautiful classic problem in physics (classic as in your grandprofessors assigned it your professor since your great grandprofessors assigned it your grandprofessors, etc and so you need to learn it too) of a conservationist pointing a tranquilizer dart gun at a monkey hanging in a tree to check on its health. At the very moment the gun fired the monkey lets go of the tree and free falls straight down. Neglecting air resistance, does the dart hit the monkey?
   • Click on the link below and experimentally test the hypothesis.
   • http://ophysics.com/k10.html (Links to an external site.)
   • In the discussion section prove or disprove that the monkey is hit regardless of the velocity of the dart, distance to the tree or altitude of the monkey.