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You will turn in your own work on a sheet of paper as evidence you did this lab.
Feel free to work in groups and help each other out - but pick different numbers so your work is different from everyone else.
Your paper will have different numbers from everyone else
1.Click Here to run the PhET simulation
2. Choose "Lab"
The Cliff Simulation: (partners will choose different heights, and launch speeds)
3. Drag the platform of the launcher up to some height - like 10 m, and rotate the barrel down to 0o so that it shoots level (Like the cliff problems we solved)
4 Choose a launch speed by dragging the "Initial Speed" selector. Do not launch the projectile yet!
5. Set up a H|V table of suvat, and calculate where the projectile will land. You know for the horizontal side, velocities, and acceleration, and for the vertical side, initial velocity, acceleration, and displacement.
6. Drag the target to where the projectile will land, and hit the red "Fire" button to launch the projectile. Feel rewarded by the three stars that briefly appear. Hit the Eraser to remove the tracks after you have basked in the glow of your triumph.
7. Now move the target either farther or nearer, and calculate using another H|V table what the initial launch velocity must be to hit your target. (The reverse of what you just did)
8. Drag the slider for "Initial Speed" to the velocity that is closest to the one you calculated. (And be frustrated that it can only be integers) Hit the "Fire" button and again be rewarded. Possibly by fewer than three stars as your velocity might not have been as accurate.
The Arc Simulation: (partners will choose different angles and launch speeds)
9. Drag the height of the launcher down so that it is launching from an elevation of 0 m. Note that it really launches from the hinge + sign, so don't worry that the barrel is higher than 0 m. Set the initial speed to 15 m/s and the angle to 30 degrees and fire the cannon. Don't erase the track, and now set the barrel to 60 degrees and fire. Notice that those two angles have the same range. Try the same thing for 40 and 50 degrees. This is always true, an angle and its complement have the same range on a level range.
10. Drag the barrel up to a jaunty angle, and select a velocity, but don't fire the cannon just yet
11. Use the Range equation (Show your work on your paper) to figure out where the projectile will land (The Range), place the target there, fire the cannon, and receive yet another three star award.
12. Move the target farther or nearer, and use the Range equation to solve for the proper launch angle (Using the same velocity) to hit the target where it now is. Show this on your paper. Move the barrel to that angle, and fire the cannon. Bask in your success!!
Keep in mind:
If you get an angle less than 25 degrees, the cannon won't go down that low, so use the angle's complement to hit the target. (90 - angle)
If you pick a range that is too far away for a given velocity, you will get a domain error when you take the inverse sine of the angle.
Arc Cliff: (EC)
13. Drag the launch platform up to some height like 6 m or so, and this time, tilt the barrel of the cannon up to some angle.
14. Using an H|V table predict where the projectile will land, place the target there, and fire the cannon. Feel very very rewarded!!!
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