Hello folks, here is a problem: The effciency of a wheel and axle system is 80% and the ratio of radius of wheel of axle is 4:1. In other to lift a mass of 20 kg, the effort required is A.60N B.62.5N C.32.5N D.250N E.50N I made use of the equation: V.R= distance moved by effort/distance moved by load = 2pieR/2pier =R/r. Bearing in mind that in the absence of friction, VR=MA Thus, MA=VR=R/r = radius of wheel/radius of axle
