EF151 Final Engineering Team EF151 Final Engineering Team Project:Project:
Austin EldridgeAustin Eldridge
Armand MendezArmand Mendez
Jack HuntleyJack Huntley
Erica HawkinsErica Hawkins
The Plexi-TrapThe Plexi-Trap
Design Design OverviewOverview
Ball Starts by rolling around rampActivates First Mouse trap which fires marble through tubeMarble hits Second Mouse trap which drops paper
Paper hits final trap that delivers the stamp
Equation Equation OverviewOverview
Gravitational Potential Energy Kinetic Energy
Conservation of Momentum
Trajectory Equation
Ball rolling down ramp(.000373slugs)(32.3ft/s/s)(.812ft) = ½ (.000373slugs)v^2v = 7.23 ft/s
Marble being fired from tube(0ft -0.146ft) = (1.08ft - 0 ft)tan(45°) - (32.3ft/s/s) / (2v^2) (1 + tan(45°)^2) (1.08ft - 0ft)^2v = 5.53 ft/s
Swing arm hitting marble(.000248slugs)(0 ft/s) + (.000496slugs)(v) = (.000248slugs)(5.53 ft/s) + (.000496 slugs)(0 ft/s)v = 2.77 ft/s
Design/Construction Design/Construction IssuesIssues
•Mouse trap spring launched marble too far
•Needed longer mouse trap levers
•Reliability of projectile
•Original tubing for ball failed due to design constraints (height limit of box) and friction/air resistance
Issue Solution•Untwist spring to lower its k value
•Solder wire onto existing levers and extend them
•Practice makes perfect!
•Replaced tubing with wooden ramps
ConclusionsConclusions Infinite Number of ways to do something inefficiently Still difficult to build something that works consistently Friction and stored energy can do a lot more than you would think it should Planning is key