course_planning:183_projects:f18_project_12 [Projects & Practices in Physics]

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====== Project 12: Part A: You spin me right round ======

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==== Project 12: Learning issues ====

  * Angular Momentum
  * Choosing an appropriate system
  * Rotational Kinetic Energy
  * Conservation of Momentum
  * Conservation of Angular Momentum

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{{183_projects:p1000804.jpg?500}} 

Last time on post-apocalypse now: Your group of scientists still at the Thunderdome, have retrieved the satellite from outer space and begun work on putting together an alternative power generator based on a merry-go-round ride from a playground. Suddenly a wormhole opens in the middle of the Thunderdome and four strangers clad in 2010's clothing emerge. They relay that they have been trapped for years in a place called the Marvel universe by someone named Korath and that they eventually escaped. Time does not flow at the same rate in the Marvel universe, and so they are shocked to find themselves in a post-apocalyptic Earth. They quickly develop a plan to rewrite history by combining the generator your scientists have been working on with exotic technology they stole from the Marvel universe to create a time machine that can send a small metallic item back in time. But first you need enough energy to power the time machine. 

The merry-go-round ride has one bar moving from the centre of the ride to a point at the edge of the ride. You also have available to you seven 5kg weights with some straps. The uniform density disk that comprises the ride is 300kg and has a radius of 2.5m. Your team which is working on the roundabout consists of 4 members. You are informed by the lead scientist of the new arrivals "Flo Rida" that the ride needs to achieve an energy of either 1036 Joules or 6500 Joules in order to generate enough electricity to send what you have decided is a paperclip back in time. 

But as plans are put in place the Thunderdome comes under attack from boar tigers and zombies. Luckily as a defensive precaution, a pit has been dug to surround the roundabout and been set on fire (zombies fall into the pit and boar-tigers are afraid of fire).

Powering the time machine to 1036 Joules will send the paperclip back to the original satellite launch and make critical machinery fail and stop the apocalypse. Powering the time machine to 6500 Joules will send the paper clip back to a time in which you knew Carver was driving his car before an accident and will cause the vehicle to explode preventing Carver from launching the satellite or any future satellites. The future (or the past) is in your hands. Choose wisely. 


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===== Project 12: Part B: You spin me right round =====

Turns out, you have access to a high-powered water hose of the kind typically used to fend off boar tigers!  This may come in handy, as the rotating platform of the generator (mass $300\,{\rm kg}$) has small little cups which would act perfectly to catch water.  The cups line the platform at a distance $r_{0}=2.5\,{\rm m}$ from the center, and the hose can generate a constant force $F_{0}=200\,{N}$.

In order to prove to Aunt Entity that this high-powered water hose is a much better approach to power the generator -- since she cannot follow your mathematical acrobatics -- you must produce a visual display of the angular momentum vector to demonstrate that the platform does indeed begin to speed up quickly.

But not too fast!  As luck would have it, your water supply is limited!  Determine how long it will take for the generator to ramp up to the required kinetic energy, using Python's graphing capabilities.

Attached below are the remnants of crazy Dr. Wiley's attempt at a simulation, however he just could not finish the job.  Take up where he left off!

<WRAP download 35%> Code for Project 13: Part B\\ Keep them in the same directory.\\ {{:183_projects:generator.py|Project 13 - Generator}}\\ {{:183_projects:physutil.py|PhysUtil Module}}</WRAP>

<WRAP info>

==== Project 12: Learning issues ====

  * Angular Momentum
  * Choosing an appropriate system
  * Rotational Kinetic Energy
  * Conservation of Momentum
  * Conservation of Angular Momentum

</WRAP>