Mission Possible B

''This page is about the Mission Possible competition for the B Division. To find more about the basic competition, go to the main Mission Possible page.''

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 to gain the maximum number of points.

=Overview= Mission Possible is all about simple machines to create a chain reaction, using a number of tasks designated by the rules to achieve the maximum points.

This type of machine is called a Rube Goldberg device. A man named Rube Goldberg made up this type of machine, and so it was named after him. A Rube Goldberg machine basically invents a way to finish an often simple task in a very complicated fashion.

For example, a machine might start with the opening task, which is dropping a quarter. The dropping of the quarter might land on a switch, which might start a motor turning that will wind a string that pulls an object a few centimeters. The pulling of the object a few centimeters would hit a lever which would open a flap that would allow a ball to roll down a ramp, hitting a mousetrap that would then release a string with a weight on it, which would hit another lever and raise an object, and so on and so forth until you reach the final task, which is raising a 9V battery and up to an optional 10 dominoes onto a platform higher than the rest of the device. This is a frustrating event at times, since it requires a lot of testing and tweaking.

The challenging part of this event is not to build the machine, but to make it reliable so it works every time. Since it is not ideal for anything to have to intervene after the reaction is started, the reaction should seamlessly work on its own every time.

=Terms Commonly Used in the Rules= Here are some terms commonly used in the rules and how they might be used in your project.

IMA and AMA
IMA stands for Ideal Mechanical Advantage.

Ideal Mechanical Advantage is the ratio of the force applied to an object to the force the object passes off. For example, if an object has an IMA of 2, that means that the force applied was doubled by the object. If the IMA of an object is $$\frac{1}{2}$$, that means that the force applied was halved by the object. If the IMA is 1, that means the force that was applied stayed the same.

For example, an object with an IMA of 2 is described as follows: if an object is pulled on with $$x$$ force, the object could pull something, but with $$2x$$ force.

AMA stands for Actual Mechanical Advantage. It takes into account things like friction and drag. AMA will not be used in scoring in Mission Possible.

Pulleys
A simple pulley is a string looped around a fixed axle. If a load is attached to one end of the string, you could pull it up, but would require the same amount of force to pull the load over the pulley as it would if you had no pulley. You could balance it by putting an equal load on the other side. Take a look at this diagram:



Pulleys can be more useful than that when there is more than one pulley wheel to a pulley system. If the load's weight is spread between two strings, there is an IMA of 2. Here is an example of a pulley system using two pulley wheels, with an IMA of 2:



Imagine that you are pulling on the string with the little arrow. If you pulled it 2 feet downwards, the hook will rise 1 foot. This is because there are two strings that lift the hook and only one string that is being pulled. 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. But remember only count the supporting lines, or the lines that are being pulled up. In the diagram, the line with an arrow is being pulled down, so it is not counted in the IMA.

In conclusion, the easy way to tell what the IMA of your pulley system is to count the number of pulley wheels.

Pulleys are easily acquirable at your local hardware store. To make the circular part of the pulley, you could also use wheels from Lego sets (without the tires, of course).

Inclined Planes
"Inclined plane" is just a fancy word for a ramp. To find the IMA of an inclined plane, divide the diagonal length of the ramp by the vertical length of the ramp.



The IMA of this ramp is $$\frac{60}{5}=12$$. Since the circular weight (the one being lifted) is less than 12 times heavier than the square weight, the square weight is able to lift the circular weight.

Wheel and Axles
A wheel and axle system can be used in many ways: to transport something, to turn something else on the axle, or to turn another wheel and axle. This diagram shows how to find the IMA of a wheel and axle simple machine. Basically, the IMA of a wheel and axle is the radius of the wheel divided by the radius of the axle.

Levers
A lever is, in basic terms, a rigid bar resting on a pivot point, or the fulcrum. To work the lever, effort must be applied to move the load, which is usually opposite the effort, across the fulcrum. There are three types of levers.
 * First Class
 * The fulcrum is in the middle, the effort is on one side, and the load is on the other. An example of a first class lever would be a seesaw or a crowbar.
 * Second Class
 * The fulcrum is to one side, the load is in the middle, and the effort is on the other side. An example of a second class lever would be a wheelbarrow.
 * Third Class
 * The fulcrum is to one side, the load is on the other side, and the effort is in the middle. An example of a third class lever would be tweezers or your elbow.



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. Therefore, if the fulcrum is moved closer to the load, the easier it is going to be to lift a load, and the higher the IMA is.

Wedges
A wedge is a simple machine that separates two objects by converting downward force to sideways force. Imagine a triangular block of wood and two adjacent bouncy balls. If you put the triangular block between the two bouncy balls and pushed down, it would separate the two bouncy balls.

Screws
Screws convert rotational force to vertical force. A screw is essentially inclined plane wrapped around a central axis. An example would be a drill or a screw for construction.

=Things to Keep in Mind While Building= 1. Make sure to label each task within your machine with little pieces of paper. That's a requirement!

2. 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.

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

4. Be safe by using a mechanical timer, so that you can fall as close to the ideal time as possible. One method would be to use a long screw to eat up time. This way, you can adjust the time it might take to finish that particular task.

5. You cannot use any loops or parallel paths in the device. Make sure that the action is linear from start to finish.

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

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

8. You cannot touch the device after it has been started without losing points. This is why the reliability of the machine is important, so you do not have to intervene in the middle.

9. Don't forget your TSL! It is required, and gives easy points.

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

11. Try to stay within the ideal time, but if that is not possible, better have it finish than fail!

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

2. Go with the simplest way possible. Don't over-complicate things, creating more room for failure. Also, build things with a durability factor. There is more reliability this 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 like tools or extra materials you need, 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. Always allow room for improvement. You don't need to have the box state-ready if you don't need it to be that good at Regionals. This will reduce the chance of failure if you keep it simple.

7. Practice with your partners and make sure that they know what they're doing!

8. You can use small pieces from Erector sets or Lego sets to get gears (not legal for some tasks), pulleys, and plates of metal with holes pre-drilled.

9. 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), and they affect the reliability factor of your machine. Stay with safer transfers and the tasks listed in the rules.

10. Double check to see if you have everything! It's bad if you realize you forgot your TSL back at your home state at Nationals!

11. Devise a system in which each of the people on the event have a designated part in setting up the machine, so that you can be ready as quickly as possible.

12. 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.