Catapult: Rotating Throwing Arm to Reduce Air Resistance?

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    Catapult Project
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Discussion Overview

The discussion revolves around the design of a catapult, specifically examining whether rotating the throwing arm to reduce air resistance is beneficial. Participants explore the implications of air resistance on projectile motion, the goals of the project, and various calculations related to projectile dynamics.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification, Homework-related, Mathematical reasoning

Main Points Raised

  • One participant suggests that rotating the throwing arm to its side could reduce air resistance due to a smaller surface area.
  • Another participant questions the significance of air resistance in the design, noting that the projectile is a standard golf ball.
  • A participant mentions that optimizing the speed of the arm is beneficial, despite issues with spring tightness affecting the mechanism.
  • Several participants inquire about the project's goals, specifically whether the focus is on distance, consistency, or other factors.
  • A participant provides specific projectile analysis data, including distance, angle, velocity, and asks about calculating centripetal acceleration using projectile velocity.
  • Additional parameters such as the radius of the arm, pull back angle, spring length, mass of the ball, and time of flight are shared, prompting further questions about calculations.

Areas of Agreement / Disagreement

Participants express varying levels of concern regarding air resistance and its impact on the design. There is no consensus on the significance of air resistance, and multiple views on the project's goals are presented. The discussion remains unresolved regarding the best approach to optimize the catapult's performance.

Contextual Notes

Participants mention specific calculations and parameters but do not resolve the mathematical steps or assumptions involved in their analyses.

kj99
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Would rotating the throwing arm (2cm by 4cm) to its side reduce air resistance due to the smaller surface area? (Imagine a palm vs karate chop scenario).
 
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Yes - is air resistance a significant factor in your design?
 
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Simon Bridge said:
Yes - is air resistance a significant factor in your design?
Not really for the projectile since it's a standard golf ball but whatever optimizes the speed of the arm is a bonus. However the tighter my springs are the more often they pop off the circle screws and the tightness also dent my pivot arm (thin metal pole).
 
May I ask what you're goal for this project is? Are you going for distance? For consistency? Something else?
 
Drakkith said:
May I ask what you're goal for this project is? Are you going for distance? For consistency? Something else?
Distance gets me a higher mark but if it breaks I won't get a mark at all lol.
 
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Drakkith said:
May I ask what you're goal for this project is? Are you going for distance? For consistency? Something else?
Projectile Analysis:
Distance = 40m
Angle = 45 degrees
Velocity = 19.8m/s
Can I use the projectile velocity to calculate centripetal acceleration?

Other Given:
Radius/length of arm: 40cm
Pull back angle: 60 degrees
Spring length: 15cm
Mass of ball is 46g
Time(ball): 2s
What else can I calculate with this?
 

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