Projectile Motion Project - Engineering Notebook
Step 1: Define the Problem
Client Company Hobby Spectacle, Inc.
Target Consumer Society
Designer Anthony and Ben
Problem Statement A leading hobby company is looking to improve an existing launcher design. The
device must launch a projectile using the materials provided. The device must be
adjustable so that projectile launches can be precise at varying distances.
Design Statement Improve an existing design, then build and test a device that will launch a projectile
varying distances with precision and accuracy.
Constraints 1. Must be constructed using the VEX equipment, and other teacher
approved materials
2. Must be adjustable to different angles ranging from 10 to 80 degrees.
3. elocity at any adjusted angle.
Must have the same initial v
4. Must launch a projectile at least 5 ft.
5. Must be able to launch either a ping pong ball or the yellow practice golf
balls.
6. Must be consistent.
7. RobotC can but is not required for this build. The use of rubber bands
and mechanical devices to change the angle are okay.
Step 2: Generate Concepts
- Research prior solutions
- Brainstorm ideas, include annotated sketches.
-
- Decide if your team will utilize the “VEX Ballistic Device Instructions” found in 4.2.3 under
resources on my.ptlw website.
Step 3: Develop a Solution
-
Step 4: Construct and Test a Prototype
- 2/12 came up with designs
- 2/13 gave up on spinning wheel design
- 2/20 tested accuracy, made tracks wider
- 2/22 tweaked for accuracy
- 2/25 tested for average range
- 2/27 lost data for average range, retested calculated expected distances
- 4/4 finished testing and comparing results
Step 1) Determine the average range of the projectile. Launch the projectile 10 times
at a fixed firing angle of 30 degrees. Measure the range of the projectile each time and
record the results in the table provided in decimal feet. Then calculate the mean range.
Measure in inches.
Example table:
Trial Number Measured Range
1 21’ 4”
2 22’ 6”
3 20 10
4 22 6
5 20 7
6 19 3
7 21 7
8 22 4
9 25
10 21 4
Mean Average 21.7
=
Step 2) Calculate the initial velocity (Vi) of the projectile. Use the calculated value for
the average range (x in the formula) in step 1 to calculate the initial velocity (Vi) of the
projectile. Be sure that you pay attention to units! (gravity = 9.81 m/s^2 but if you didn’t
measure x in meters then you will need to convert either the gravity or x value
accordingly)
28 feet per second
Step 3) Calculate the ideal range of the projectile at various firing angles. Use the
calculated value for initial velocity and specified firing angles to calculate the ideal range
of the projectile at each angle. Record the values in the table. Again, pay close attention
to units!
Example table: R = v02 sin 2θ0/g
Angle Range - Calculated Range - Actual Difference between
calculated and actual
10° 8.6 8 10 -3.8 in
20° 16.11 13 2 2 feet 11.7 in
30° 21.7 19 7 2 feet 1.4 in
40° 24.68 21 3 3 feet 5.16 in
45° 25.1 24 1 1 foot .2 in
50° 24.68 22 4 2 feet 4.16 in
60° 21.7 19 5 2 feet 3.4 in
70° 16.11 18 8 -2 feet 6.7 in
80° 8.6 16 6 -7 feet 10.8 in
Step 5: Evaluate the Solution
- Prototype Results
- How accurately could you hit targets based off of your calculations? We seemed
to be off in the 2 feet area each time, so I think we were precise in our
inaccuracy.
- How did your machine compare to others in the class? Other groups tried to do
the spinning wheel design too, but gave up as it was too difficult. Other groups
also had pieces of metal attached to the rubberband that would hit the ball
whereas ours worked like a slingshot.
- Reflect on the overall project and the skills you applied throughout the project
- How did you do with collaborating with others? Or how was the group dynamics?
What could you have done to improve your teamwork? When I scrapped the
other design I was working for on our ball launcher, I felt that all the work I had
done was meaningless and I had wasted the groups time. My partner ended up
doing most of the work on the first successful part while I was working on the
other
- How was your time management? Our time management was good, and we
finished on time.
- What did you do well in this project? What do you still need to work on when
working on large projects and in groups? I need to take on a bigger part of the
work
- Reflect on the engineering concepts learned so far this year (calculations/building/etc)
- What concepts (simple machines, electricity, power/work, programming logic,
etc) did you apply in this project? We converted potential to kinetic energy by
launching our ping pong balls. We used an inclined plane to angle our shots.
- What did you find difficult in regards to the engineering concepts? This part
wasn't that difficult as I have already taken physics.
Step 6: Present the Solution
“I will present informally in class as well as present this project on my portfolio.”
