Solution:
Given,
Load (L) = 50 kg which means the actual load is 50 kg × 10 m/s2 = 500 N [∵ F = mg ],
Effort (E) = 120 N,
Effort distance (ED) = 20 cm,
- Load distance (LD) = ?
We have, from the principle of a simple machine,
L × LD = E × ED
Or, 500 × LD = 120 × 20
Or, \(LD=\frac{2400}{500}\)
∴ LD = 4.8 cm
- Mechanical advantage (MA) =?
We have,
Mechanical advantage, \(MA=\frac{L}{E}\)
Or, \(MA=\frac{500}{120}\)
∴ MA = 4.17
- Velocity ratio, VR =?
We have,
velocity ratio, \(VR=\frac{ED}{LD}\)
Or, \(VR=\frac{20}{4.8}\)
∴ VR = 4.17
- Efficiency (η) =?
Since MA = VR the efficiency of the given lever is 100%
Also using the formula for efficiency of a simple machine. we have,
Efficiency, \(η=\frac{MA}{VR}\times 100\%\)
Or, \(η=\frac{4.17}{4.17}\times 100\%\)
∴ Efficiency, η = 100 %
The given lever is 100% efficient. Which means that the lever is an ideal lever.