A wheel and axle is used to raise a load of 500N by the application of an effort of 250N. If the radii of the wheel and the axle are 0.4cm and 0.1cm respectively; the efficiency of the machine is?

A. 20 %
B. 40 %
C. 50 %
D. 60 %

Correct Answer:

Option C – 50 %

Explanation

Efficiency = M.A/V.R X 100/1 M.A = Load/Effort = 500/250
= 2
V.R. = radius of wheel/radius of axle = 0.4/0.1 = 4.
therefore Efficiency = 2/4 x 100/1 = 50 %