Simple Machines
There are three basic kinds of simple machines that make up the simple mechanisms.
Inclined Plane
This is an incline plane. If you would wanna move something heavy you would use an inclined plane. Although you must move the object more it will take less effort. As you cam see in the picture depennding on how much length the slope has, is the amount of Ideal mechanical advantage. For example if the slope was 4 times longer than the hight you would have a ideal mechanical advantage of 4:1. To find the Actual Mechanical advantage you must devide the full effort to lift the object by the slope effort.
Screw
This right here is a screw which i think every one is familiar with. A screw is basicly a really long inclined plane wrapped around a pole in a rotational motion. To find the Ideal Mechanical Advantage you must devide the circumfirance of the head of the screw over the length of the pitch. To FInd the Actual Mechanical Advantage you must devide the effort requried to pierce over the effort yoiu actually put in.
Wedge
This is a wedge which can be found in many things such as a lumber axe. When you dont cut a piece of wood all the way through you use the axe as a wedge and force the wood to split. To find the Ideal Mechanical Advantage you must take the hight of the wedge and divide it over the length of the wedge. To find the Actual Mechanical Advantage you must divide the force that it takes to split something over the force you push the wedge down.
Lever
This is the lever that mer and my group came up with. As you can see the lever is a first class lever cause the fulcrum is located between the Effort and the Resistance. Since the Resistance is closer to the fulcrum and the Effort is futher away the MA < 1.
Calculations
Lever Moment = d1*F1 = d2*F2 1.1lbs.* 2.1in. = .22lbs * 10.5 in. 1.1*2.1=2.31 .22*10.5= 2.30
ANSWER: 2.31 does not equal 2.30 but the calculation is only a tenth off
Lever IMA = De/Dr 10.5/2.1 IMA: 2.1
Lever AMA = Fr/Fe 1.1lbs / .22lbs = 5 AMA: 5
Efficiency = (AMA/IMA)100 (2.1/5)100 = 42 EFFICIENCEY: 42%
ANSWER: 2.31 does not equal 2.30 but the calculation is only a tenth off
Lever IMA = De/Dr 10.5/2.1 IMA: 2.1
Lever AMA = Fr/Fe 1.1lbs / .22lbs = 5 AMA: 5
Efficiency = (AMA/IMA)100 (2.1/5)100 = 42 EFFICIENCEY: 42%
Conclusion
Basically the lever will either make it harder or easier for you to lift the counter weight. If your resistance is closer to the fulcrum and the effort is further away you will use less effort cause when you have a longer distance the a small amount of weight can lift a heavier but it would lift it slowly. On the other hand if your resistance is further away and your effort is closer then you will have to use much more effort cause the weight of the resistance will be multiplied cause of the length. The only benifit about this is that you will lift the resesistance much faster.
Wheel and Axle
This is the wheel and axle my team created. The axle is in the middle and the resistance is the weight that is hanging from the shaft.the effort to turn the wheel is at the shaft placed on the side of the gear.
Calculations
Wheel and Axle IMA = De/Dr 3.1in./1.6in 3.1/1.6= 1.14 IMA: 1.93
Wheel and Axle AMA = Fr/Fe .22/ .14 lb .22/.14=1.46 AMA: 1.46
Efficiency = AMA/IMA (1.46/1.93)100 .75*100 = 75 EFFICIENCY: 75%
Wheel and Axle AMA = Fr/Fe .22/ .14 lb .22/.14=1.46 AMA: 1.46
Efficiency = AMA/IMA (1.46/1.93)100 .75*100 = 75 EFFICIENCY: 75%
Conclusion
The wheel and axle is basically a 3rd class lever that spins in a circle allthough the resistance is on the fulcrum which in this case is the axle. Basically the bigger wheel is the more AMA and IMA you will have cause you spread the resistance over a bigger daiameter. The only down side about having a bigger wheel is that it takes longer to rotate the wheel which means that it will take longer to rotate the axle.So having a bigger wheel will give you a bigger ratio advantage.
Pulley
This is the pulley that me and my team made. As you can see this is a first class pulley cause the pulley stays in place. It must pull a 500g about 2.3 ft.
Calculations
Pulley IMA = 2^3 = 2*2*2 = 8 IMA= 8
Pulley AMA = 1.1lbs/.35 lbs. 1.1/.35 = AMA= 3.1
Efficiency= AMA/IMA 3.1/8 = .38 .38*100 = 38 EFFICIENCY= 38%
Pulley AMA = 1.1lbs/.35 lbs. 1.1/.35 = AMA= 3.1
Efficiency= AMA/IMA 3.1/8 = .38 .38*100 = 38 EFFICIENCY= 38%
Conclusion
The pulley i think is in a class of its own. It uses the pull of opposite strings to cut the weight down were you actually can use a smaller weight to pull up a bigger weight as seen on this picture. The system has three pulley and one that stays in place so it cuts down the effort needed considerably. The more pulleys you have the more MA you will have and the easier it will be to pull. The down side though is that you need to pull more string for every pulley you add so yeah.