A wheel and an axle is used to raise a load whose weight is 800N when an effort of 250N is applied. If the radii of the wheel and axle are 800mm and 200mm respectively, the efficiency of the machine is by Sunday | Nov 7 | Physics JAMB | 0 comments A. 90% B. 80% C. 85% D. 87% Correct Answer: Option B – 80% Users Also Read These:What effort will a machine of efficiency 90% apply…The diagram represents a block-and-tackle pulley…A wheel and axle of radii 800mm and 200mm…What effort will a machine of efficiency 90% apply…The diagram above illustrates a block and tackle…