Difference between revisions of "Mission Possible B"

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'''Mission Possible B''' is very similar to formerly-run [[Mission Possible C]]. The B division version does not include any energy sources outside of gravity and is based on energy transfer between different simple machines such as levers of different classes, pulleys, screws, inclined planes, wheel and axles, wedge etc. Each simple machine is specifically explained in the rules. Any deviation from these rules will result in the loss of points. ex. an wedge must be used as a "wedge" to lift or separate something. A wedge cannot just "push something off of a surface, it must exhibit "genuine wedge action". Rules for this even are very specific but do allow a great amount of creativity in how you use and connect your machines. The k.i.s.s. principal is your friend: keep it simple stupid. Reliability is the goal! The task sequence list (TSL) is also very important. You only receive points you claim to get on the list, no more, but you can get less.
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'''Mission Possible B''' is an event in which teams make a Rube Goldberg device which uses certain tasks and runs as close as possible to the ideal time.
 
 
Tip: KNOW THE RULES! Know them better than you know your best friend! They are your best friend when you follow them, but can quickly become your worst enemy when you decide not to look at the details.
 
 
 
Also: Remember to know what simple machines you use so that when you tell the judge you will get the right amount of points. If you don't know them you wont get any points.
 
  
  
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[[File:Simplemachines.png|thumb|center]]
 
[[File:Simplemachines.png|thumb|center]]
*Wedge
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<ul>
*Screw
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<li>Wedge</li>
*Pulley
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<li>Screw</li>
*Wheel and Axle
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<li>Pulley</li>
*Inclined Plane
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<li>Wheel and Axle</li>
*Lever
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<li>Inclined Plane</li>
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<li>Lever</li>
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</ul>
  
 
Each machine is unique in its own way in that they can change the distance or power a force is applied in different ways. They also may change the direction in which a force is applied.  
 
Each machine is unique in its own way in that they can change the distance or power a force is applied in different ways. They also may change the direction in which a force is applied.  
  
 
==IMA==
 
==IMA==
On the rules sheet, you may have seen "IMA" quite a lot of times. Like me, you were probably wondering, "What is IMA?" Instead of making up acronyms, let's take a look at the concept of Ideal Mechanical Advantage.  
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IMA stands for Ideal Mechanical Advantage.
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Ideal Mechanical Advantage is the multiplier of the force from what was applied to the result force. So when you have an IMA of 2, that means that the force you applied was doubled by the simple machine. When you have an IMA of <math>0.5</math> or <math>\frac{1}{2}</math>, that means that the force you applied was halved by the simple machine. When you have an IMA of 1, that means the force that you applied stayed the same. '''Key Concept: With simple machines, you exchange power with distance.'''
  
Ideal Mechanical Advantage is the multiplier of the force from what was applied to the result force. So when you have an IMA of 2, that means that the force you applied was doubled by the simple machine. When you have an IMA of .5, that means that the force you applied was halved by the simple machine. When you have an IMA of 1, that means the force that you applied stayed the same. '''Key Concept: With simple machines, you exchange power with distance.''' So let's take a look at a simple machine with an IMA of 2. If you applied 2 units of force for 4 meters, the result would be 4 units of force for 2 meters. This may seem confusing without a proper explanation and understanding of physics, but you can read a physics textbook if you want to fully understand the concept of simple machines. Now, let's take a look at each individual type of simple machine.  
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An example of an IMA of 2: If you applied 2 units of force for 4 meters, the result would be 4 units of force for 2 meters. This may seem confusing without a proper explanation and understanding of physics, but you can read a physics textbook if you want to fully understand the concept of simple machines. Now, let's take a look at each individual type of simple machine.
  
 
==Pulleys==
 
==Pulleys==
I think this is the easiest simple machine to start with. A simple pulley is a string around a mounted circular axle. A load can be attached to one end of the string. It would require the same amount of force to pull the load up as normal. You could balance it by putting an equal load on the other side. Take a look at this diagram:  
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A pulley is an easy simple machine to implement. A simple pulley is a string around a mounted circular axle. A load can be attached to one end of the string. It would require the same amount of force to pull the load up as normal. You could balance it by putting an equal load on the other side. Take a look at this diagram:
  
 
[[File:Simple pulley.png|thumb|center]]
 
[[File:Simple pulley.png|thumb|center]]
  
Now, let's take a look at this type of pulley called a "gun tackle".
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This type of pulley is called a "gun tackle".
  
 
[[File:Pulleyima2.png|thumb|center]]
 
[[File:Pulleyima2.png|thumb|center]]
  
Imagine if you were to pull on the string with the little arrow. If you were to pull on it for 10 meters, the hook will rise 5 meters. This is because there are two strings that lift the hook and only one string that is being pulled. This pulley will have an IMA of 2. This means that you can lift a heavy load as if it were only half as heavy. Now, imagine if three strings were attached to the hook. What would be the IMA of the pulley now? The answer is 3.  
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Imagine if you were to pull on the string with the little arrow. If you were to pull on it for 10 meters, the hook will rise 5 meters. This is because there are two strings that lift the hook and only one string that is being pulled. This pulley will have an IMA of 2. This means that you can lift a heavy load as if it were only half as heavy. Now, imagine if three strings were attached to the hook. The IMA would now be 3.
  
Using the pulley in your device- For one task you are to design a pulley with an IMA greater than one to lift an object. I recommend you use the pulley system pictured above. To make the circle things, try using Lego wheels.
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Pulleys are easily acquirable at your local hardware store. You can also use pieces from sets, such as LEGO or K'nex.
  
 
==Inclined Planes==
 
==Inclined Planes==
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==Levers==
 
==Levers==
A lever consists of 4 elements- a flat board, the fulcrum (the stationary point on which the board rests on, usually resembles a triangle), the effort (the force or object that is usually pushing down) and the load (the force or object that moves as a result of the effort force).  
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A lever consists of 4 elements- a flat board, the fulcrum (the stationary point on which the board pivots, usually resembles a triangle), the effort (the force or object that is usually pushing down) and the load (the force or object that moves as a result of the effort force).
There are three types of levers.  
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There are three types of levers.
 
*First Class
 
*First Class
**Seesaw, where the fulcrum is in between the effort and load.
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**The fulcrum is in the middle, the force is on one side, and the load is on the other.
 
*Second Class
 
*Second Class
**Wheelbarrel, where the fulcrum is at the end and load is in the middle.  
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**The fulcrum is to one side, the load is on the other side, and the force is in the middle.
 
*Third Class
 
*Third Class
**the fulcrum is at the end and the effort is in the middle
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**The fulcrum is to one side, the load is in the middle, and the force is on the other side.
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[[File:Levers.jpg|1st, 2nd, and 3rd class levers respectively]]
  
 
To find the IMA of a lever divide the distance between the fulcrum and the effort by the distance between the fulcrum and the load.
 
To find the IMA of a lever divide the distance between the fulcrum and the effort by the distance between the fulcrum and the load.

Revision as of 19:58, 9 April 2012

Mission Possible B
& Event
Forum Threads
2012
There are no tests available for this event
Images Image Gallery
There are no question marathons for this event
This event was not held recently in Division B
This event was not held recently in Division C


Mission Possible B is an event in which teams make a Rube Goldberg device which uses certain tasks and runs as close as possible to the ideal time.


Physics of Simple Machines

Mission Possible is all about simple machines. What exactly is a simple machine? A simple machine is a machine that uses a concept to increase distance or power of a force. There are 6 types of simple machines.

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  • Wedge
  • Screw
  • Pulley
  • Wheel and Axle
  • Inclined Plane
  • Lever

Each machine is unique in its own way in that they can change the distance or power a force is applied in different ways. They also may change the direction in which a force is applied.

IMA

IMA stands for Ideal Mechanical Advantage.

Ideal Mechanical Advantage is the multiplier of the force from what was applied to the result force. So when you have an IMA of 2, that means that the force you applied was doubled by the simple machine. When you have an IMA of Failed to parse (Missing <code>texvc</code> executable. Please see math/README to configure.): 0.5 or Failed to parse (Missing <code>texvc</code> executable. Please see math/README to configure.): \frac{1}{2} , that means that the force you applied was halved by the simple machine. When you have an IMA of 1, that means the force that you applied stayed the same. Key Concept: With simple machines, you exchange power with distance.

An example of an IMA of 2: If you applied 2 units of force for 4 meters, the result would be 4 units of force for 2 meters. This may seem confusing without a proper explanation and understanding of physics, but you can read a physics textbook if you want to fully understand the concept of simple machines. Now, let's take a look at each individual type of simple machine.

Pulleys

A pulley is an easy simple machine to implement. A simple pulley is a string around a mounted circular axle. A load can be attached to one end of the string. It would require the same amount of force to pull the load up as normal. You could balance it by putting an equal load on the other side. Take a look at this diagram:

Simple pulley.png

This type of pulley is called a "gun tackle".

Pulleyima2.png

Imagine if you were to pull on the string with the little arrow. If you were to pull on it for 10 meters, the hook will rise 5 meters. This is because there are two strings that lift the hook and only one string that is being pulled. This pulley will have an IMA of 2. This means that you can lift a heavy load as if it were only half as heavy. Now, imagine if three strings were attached to the hook. The IMA would now be 3.

Pulleys are easily acquirable at your local hardware store. You can also use pieces from sets, such as LEGO or K'nex.

Inclined Planes

"Inclined plane" is just a fancy word for a ramp. Finding the IMA of an inclined plane is easy. Simply divide the diagonal length of the ramp by the vertical length of the ramp.

Ramp.png

The IMA of this ramp is 12 (60/5). Because the circle on the ramp is less than 12x heavier than the one hanging, the one hanging pulls the circle up the ramp.

Wheel and Axles

Levers

A lever consists of 4 elements- a flat board, the fulcrum (the stationary point on which the board pivots, usually resembles a triangle), the effort (the force or object that is usually pushing down) and the load (the force or object that moves as a result of the effort force). There are three types of levers.

  • First Class
    • The fulcrum is in the middle, the force is on one side, and the load is on the other.
  • Second Class
    • The fulcrum is to one side, the load is on the other side, and the force is in the middle.
  • Third Class
    • The fulcrum is to one side, the load is in the middle, and the force is on the other side.

1st, 2nd, and 3rd class levers respectively

To find the IMA of a lever divide the distance between the fulcrum and the effort by the distance between the fulcrum and the load.

Wedges

Screws

Key Points

1. The action of each simple machine will determine which of the eight types of simple machines it is most like.

2. Find out when the Simple Machines List is to be given to the Tournament Director. Meet the deadline. Resist changing the device after this. Spend time perfecting the device.

3. Label the actual simple machines and make sure that the numbers match the Simple Machines List.

4. The simple machines of the same type do not have to be unique. Note that consecutive machines of the same type (even though unique) still only count as one machine.

5. Make sure to meet the general requirements, since failure to do so is a severe penalty (you get second tiered). Make sure that all parts of the device, including the outer walls and base plate fall within the legal dimensions of the device.

6. Be safe by using a mechanical timer. The sand and water in the pulley system should account for any needed use of extra time.

7. Do not use any loops or parallel paths in the device. Make sure that the action is linear from start to finish.

8. The highest part of the device automatically designates the top boundary of the device.

9. You can start parts of the device operating before the pulling of the string (such as pendulums, springs, etc.).

10. You will not be allowed to touch the device at or beyond the next-to-last simple machine. Make sure that this works every time.

11. Remember that you will probably lose any positive points for time if your device fails to complete the task, but continues to operate.

12. The only thing that should control how much the mass is lifted is the operation of the last paddle wheel ( no pulleys, motor, etc)


Tips

1) Know your task sequence list as well as you know your rules. Be able to explain everything.

2) Go with the simplest way possible. There is less to be fixed that way.

3) Draw all your designs and keep them together in case something doesn't work and you need to build something new.

4) Prepare for every scenario you can think of. Bring just-in-case items, but don't go overboard.

5) Test your device prior to competition many, MANY times--do not just build it and bring it in.

6) Practice with your partner and make sure that s/he knows what s/he's doing!

7) KISS! Keep it simple, stupid. This has been mentioned many times but it can not be stressed enough. Yes, domino trains are cool. Baking soda and vinegar inflating balloons is even cooler. However, they don't count for anything except maybe time (but there are easier ways to make your device go longer), so it would be a bad idea to use them. Stay with safer transfers and the tasks listed in the rules.

8) And last but not least, KNOW THE RULES. You can even tape them to your box if the event supervisor doesn't agree with something in your device to back yourself up.

See Also