Lab Activity: Projectile Motion
Include the following in your lab report:
1. The title of the lab activity
2. The date the lab activity was performed
3. The goal(s) of the lab activity
4. A description of the lab activity (procedures, sketches or pictures)
5. Data collected in the lab activity
6. Analysis of data and sample calculations
7. Conclusion(s) (Answer the questions posed in the lab)
There is no error analysis in this lab activity.
There are 5 parts to this lab. The first 4 parts use the simulation shown below. The final part is a hands-on activity. Click the "Intro" simulation to begin. For activities 1 through 4, use the controls in the simulation to fire the projectiles (by pushing the red firing button) at various angles and with various initial speeds. Don't forget that the definition of the "range" is the distance traveled in the x-direction to get back down to the original firing height. The trajectory shown in the simulation starts at the base of the cannon.
You can use the tools (located at the top of the simulation) to make any measurements you need. Record all of your work in your lab notebook, including the calculations you make and results of the simulations.
a. Calculate the range of a projectile with an initial speed of 16 m/s and a firing angle of 35° when the cannon is on the ground. After you determine the answer, adjust the parameters to those values in the simulation and fire the cannon. Record your results and the results given by the simulation.
b. Change the mass of the projectile in the simulation by choosing several different objects as projectiles. Do you think this change will have any effect on the range? Fire the cannon with a different mass. Does this change have any effect? Why or why not?
a. Calculate the maximum height of a projectile fired at 8 m/s and a 50° firing angle. After you determine the answer, adjust the parameters in the simulation to these new values and fire the cannon. Record your results and the results given by the simulation.
b. Examine the structure of the equations you used to determine by what factor the maximum height would change if you doubled the initial speed. Check your thinking by changing the initial speed on the simulation to 16 m/s. Record your results.
Calculate the ranges for a projectile with an initial speed of 15 m/s shot at a 40° angle and the same projectile shot at a 50° angle. How do the results compare? Use the simulation to check your work. Record your findings. Try the same activity with angles of 25° and 65°. What can be said about firing a projectile at complementary angles?
Repeat activity 3, this time finding the total horizontal distance traveled when the cannon raised 10 m off the ground. This distance is no longer referred to as the range (because Δy ≠ 0), and you cannot use the range equation to find it. Instead, you simply need to use the basic kinematic equations for projectiles. Compare and contrast your results between activity 4 and activity 3. Explain any differences.
This is the hands-on part of the activity that requires a partner or two. Toss any small round object (a baseball, for example) and take series of images (use a cell phone) of its parabolic trajectory (from the side). Determine the intitial speed of the toss by analyzing the images and using measurements you make. You can make the measurement via the image(s) as long as there is something in the image that is of known height or length that can be used as a reference or you can actually measure the range of the toss or its max height, etc. You must include at least one image in the lab report and throughly explain how you calculated the initial speed. Please use an image editor like lunapic (www.lunapic.com) to add graphics to your image (measurements and vectors, for example) that illustrate your work.