13. Extending Arm Analysis
Mass of Scissor Arm = 0.075 kg
Length of Arm (Extended) = 41.82 cm
Length of Arm (Compressed) = 13.11cm
Displacement = 28.71
Desired time of travel to reach max distance desired = 10
Factor of Safety = 2.5
Energy and Power Calculations
Calculating Needed Energy
Ave Velocity = Displacement/time
= 0.029 m/s
Maximum Velocity = 2(Ave Velocity)
= 0.057 m/s
Kinetic Energy = 0.5(Mass)(Max Velocity)^2
= 1.236E-4 J
Energy Calculated with F.o.S. = 3.091E-4 J
Power Calculated with F.o.S. = 3.091E-5 W
Therefore E(available)>>E(needed)
there is enough energy provided by the motors to power the scissor arm
Comparison of Experimental Results to Theory
These results are based on the very optimistic assumption that
friction is negligible. In reality friction was a high risk factor. But in the end
we still had enough energy from the motor to power the arm.
Erika Moreno
15. MagicBox
Final Design + Prototype
● Utilizes elastic properties of ABS plastic
● Downsides:
○ Dependant upon weight
○ You can only grab six balls maximum
Risk Reduction prototypes determined
optimal distance between stretchy parts
was 1.59 inches
Samuel Lechtman
