Compound Machine

 Build a Compound Machine

 

 

        After testing the simple machines we were handed a new task which was to make a compound machine out of the pulley, wheel and axle, and the lever (we were not allowed to use the inclined plane) without an ideal mechanical advantage.  You most be thinking if there is no ideal mechanical advantage what was the point in combining the machines? Well to answer that question we had to try and get as high of a mechanical advantage as we could get.  And whatever mechanical advantage we got would be our grade which was written on the board what you have to get to get a certain grade.

 

       When we were working on this project we weren't really worried about what the other groups were making/ building, because we were focused on getting at least an A- on the machine.  Even though we weren't worried about the other groups it was still cool to see what some of them came up with especially Christian Merkle.  A problem we had with this project was finding a secure place to put our Lever, when attached to the pulley, and crank.  So to solve this problem we drilled 2 holes through the pieces of wood holding the pulley up right and pulled a piece of string through it connecting the Wheel & Axle, and Lever together while still incorporating the pulley in the middle.  At first our method didn't really work but we made some adjustments, and at the end it all came together getting us a mechanical advantage of 39 which gave us a B+, not what we wanted to get but it was acceptable.  We could have focused more on our project instead of talking to the other groups and getting distracted.

 

      The most difficult part about this assignment was putting the three machines together, and having them all work together to move the nails, and the get an accurate read on the spring scale.  The mechanical advantage my group got was extremely surprising because it took a while to get the three together.  I could apply the knowledge that I learned from this project to a future experiment that involves putting together 2 other machines or invention, because now I know what I did wrong and what I have to fix in the future.             

 

Simple Machines

Simple Machines



 

                        Wheel & Axle
                      Zach & Finbarr

                          Lever
                     Ian & Finbarr 

 

 Inclinede Plane Ian & Zach
                

                           Pulley

                  Zach, Ian & Finbarr

 

               We made simple machines to test for a specific mechanical advantage assigned by Mr.Atkins.  The ideal mechanical advantage for the Wheel and Axle, Inclined plane, and Lever was 6; and the ideal mechanical advantage for the pulley was 2.  The way we test for the mechanical advantage was using a box of nails as a weight for the Lever, inclined plane and pulley, then using the spring scale to get the measurement of the input force for all the machine. 

 

               When we tested the machines against the other groups we tied for 3rd in the Wheel &Axle with 69.99% efficiency, then we tied for 3rd again in the Inclined Plane with 36.5% efficiency, next we tied for first in the Lever having a mechanical advantage of 73% efficiency, finally our pulley got 4th with 73% efficiency.  It was hard to pick a winner because of all the disqualifications of the other groups machines, but if it was up to me, I believe my group won considering we were not disqualified and we placed top 3, 3 times out of the four machines.

 

               For the results my group did not get 100% efficiency in any of our machines because we were a little off on the measurements of our machines which changed the mechanical advantage drastically.  When our machines tested they function well but not well enough to hit 100% efficiency.  We could have changed the measurements of the wood we used mainly for the wheel & axle because the circle we cut out originally was way to big, so we had to cut out a last second circle which wasn't the  exact measurement we needed to get 100% efficiency in the wheel & axle.