In a wheel and axle mechanism the diameters of the wheel ...
In a wheel and axle mechanism the diameters of the wheel and axle are 40cm and 8cm respectively. Given that the machine is 80% efficient, what effort is required to lift a load of 100N?
20N
25N
50N
80N
Correct answer is B
Efficiency = work done by handwork done by effort
80 = 100×8E×40 x 1001
E = 25N