Physics Practice Test – Machines (Questions with Answers & Explanations)

Which of the following equations for the efficiency of a machine is correct? (WASSCE 2008)

Which of the following statements correctly defines a simple machine? A device _____ (WASSCE 2011)

A. that can produce electric current.
B. which can only carry people from one place to another.
C. with which work can be done easily.
D. which changes the state of rest or of uniform motion of an object.

A machine whose efficiency is 60% has a velocity ratio of 5. If a force of 500N is applied to lift a load P, what is the magnitude of P? (UTME 2004)

(a) 750 N     (b) 4166 N    (c) 500 N    (d) 1500 N

A block and tackle system has six pulleys. A force of 50 N applied to it lifts a load of weight W. If the efficiency of the system ¡s 40%, calculate W.

A. 300 N   B. 200 N   C. 140 N   D. 120 N

In a wheel and axle mechanism, the diameters of the wheel and axle are 40 cm and 8 cm respectively, given that the machine is 80% efficient, what effort is required to lift a load of 100 N? (UTME 1988)

(a) 20 N   (b) 25 N   (c) 50 N   (d) 80 N