A wheel and axle of radii 800mm and 200mm respectively is used to raise a body of weight 800N by the application of 250N. Calculate the efficiency of the machine
- 85%
-
80%
- 60%
- 20%
The correct answer is: B
Explanation
V.R = \(\frac{R}{r} = \frac{800}{200} = 4\)M.A = \(\frac{L}{E} = \frac{800}{250} = 3.2\)
y = \(\frac{M.A}{v.R} \times \frac{100}{1} = 80\)%