Catapult Activity

Velocities at different positions (visualized in graphs)

Initial Velocity

Short: 3.55 m/s

Tall: 3.85m/s

Peak Velocity

3.34m/s

3.63 m/s

Even Velocity

-3.64 m/s

-3.23m/s

Final Velocity

-7 m/s

-7.38 m/s

Graphing the Data
(Y over X)

Small Velocity (m/s) over time (s)

Small Height (m) over Distance (m)

Large Velocity (m/s) over time (s)

Large Height (m) over Distance (m)

Reflection

Sources of Error: Actual height variation
Measurements of both max distance and height
Wrist position/angle
Rounding in some calculations
Calculations themselves were not perfect
General Human error
Times may be a little off.

Improvements: We can have a fixed height from where the person was launched so the data is more accurate.
We can also have more people looking for the exact height and distance, since this was approximated based on our vision and the video.

Our Data

Long Base

Short Base

Design:
• The catapult is hand held so the same person must conduct all tests starting at a marked position.
• The person firing the catapult must have their arm and wrist parallel to the floor.
• The person must make a fist with their hand and have two fingers within the side handles, and their thumb must hold a protractor at the point where the catapult starts to bend to get the target angle.
• A measuring tape should be hung vertically (easy to do at stairwell).
• A person should record the time and take a video to find the max height.
• Mark wherever the marshmallow first hits the ground.
• Once vertical distance and time has been calculated take measuring tape and measure the distance from the launch point to where the marks are.
• Also the catapult is extendable just pull on the top to shift the distance from the base.

Does the length of the base of the catapult affect the distance or velocity the marshmallow travels?

Our Hypothesis

If the distance between the center of mass of the base is increased then the projectile will travel a smaller horizontal distance but have a greater max height.

Start Heights,
Short: 1.68 m
Long: 1.73 m

Independent variable

The distance between the base and height of the catapult.
Short: 34.2 cm Long:38.5 cm

Only the distance between the base and the height was altered during the experiment, and confounding variables were carefully accounted for.

Dependent variables

Distance(m), Max Height(m), Velocity(m/s) dependent on the height of the launch.

Start Here and Go Clockwise!

Conclusion

Ultimately, the catapult with the longer/shorter base will lead to a greater distance, height, and therefore, a greater velocity.