Output work/input work × 100% = efficiency
Output work (J) = output force (N) × output distance (m)
6 N × 0.085 m = 0.51 J
Output work: 0.51 J
Input work (J) = input force (N) × input distance (m)
3.5 N × 0.165 m = 0.5775 J
0.51/0.5775 × 100% = 88.3 %
Efficiency: 88.3%
Ideal Mechanical Advantage
Lever: output fulcrum = 25 cm
input fulcrum = 34 cm
Pulley: block and tackle: 3
Fulcrum: 34/25 = 1.36
1.36 × 3 = 4.08
Ideal Mechanical Advantage = 4.08
Actual Mechanical Advantage
Input force: 350 grams
Output force: 600 grams
600/350 = 1.7
Mechanical Advantage: 1.7
Analysis
One main reason why ideal mechanical advantage is always more than actual mechanical advantage is because of friction. In every machine (even ours), a certain amount of work is alway wasted on overcoming friction. An ideal mechanical advantage is what the actual mechanical advantage would be without friction. Which means that the actual mechanical advantage is always lower because of the friction. The less friction there is, the higher the actual mechanical advantage is. This is proven by looking at both our ideal and actual mechanical advantages. We see that 2.38 of mechanical advantage is being wasted on friction. Another fact is that the less the friction, the closer the output work is to the input work. When they are closer together it means that the efficiency is closer to 100 %. Of course it is impossible to get a machine which is 100% efficient. This is due to friction. Our machine is 88.3 % efficient. This means that 11.7 % is being wasted on friction.
Analysis
One main reason why ideal mechanical advantage is always more than actual mechanical advantage is because of friction. In every machine (even ours), a certain amount of work is alway wasted on overcoming friction. An ideal mechanical advantage is what the actual mechanical advantage would be without friction. Which means that the actual mechanical advantage is always lower because of the friction. The less friction there is, the higher the actual mechanical advantage is. This is proven by looking at both our ideal and actual mechanical advantages. We see that 2.38 of mechanical advantage is being wasted on friction. Another fact is that the less the friction, the closer the output work is to the input work. When they are closer together it means that the efficiency is closer to 100 %. Of course it is impossible to get a machine which is 100% efficient. This is due to friction. Our machine is 88.3 % efficient. This means that 11.7 % is being wasted on friction.
