The velocity ratio and efficiency of a system of pulleys are 6 and 80% respectively. How much effort is required to lift a load of mass 120kg with this system? (g=10ms-2)
A
25N
B
90N
C
96N
D
250N
E
960N
Verified Correct Answer: D.
Physical Principles & Numerical Solution
Efficiency = M.A/V.R x 100%
= 80/100 = 120 x 10/E
E = 250N
Source: Myschool Past Questions Archive (Record #25203)