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A wheel and axle is used to raise a load of 500 N by the app...

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

A.

20 %

B.

40 %

C.

50 %

D.

60 %

Correct answer is C

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 %