The efficiency of the pulley system shown above is 80%. find the effort E required to lift the load of 1200N
Attached Figure / Diagram
A
275N
B
325N
C
375N
D
573N
Verified Correct Answer: C.
Physical Principles & Numerical Solution
VR = No. of pulleys = 4
Efficiency = \(\frac{M.A}{V.R}\)
cross multiply
\(\frac{80}{100} * V.R\) = M.A
\(\frac{80}{100} * 4\) = M.A
M.A = 3.25
where M.A = \(\frac{load}{effort}\)
∴ Effort = \(\frac{1200}{3.2} * V.R\)
= 375N
Source: WAEC / JAMB / NECO Classroom Archive (Record #14487)