The efficiency of a wheel and axle is 100% and the ratio of their radii is 5:1. calculate the effort required to lift a load of mass 20kg using this machine, [g = 10 m s\(^{-2}\)]
A
20N
B
25N
C
40N
D
100N
Verified Correct Answer: C.
Physical Principles & Numerical Solution
VR = 5:1 or 5
Load = 20kg or 200N
MA = \(\frac{200}{E}\)
Efficiency% = \(\frac{MA}{VR} * 100\)
100% = \(\frac{200}{5E} * 100\)
5E = 200
E = 40
Source: WAEC / JAMB / NECO Classroom Archive (Record #63094)