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

If a heavy barrel is rolled up a plane inclined at 30^o to the horizontal, its velocity ratio will be ____ (UTME 2009)

A. 3.0   B. 3.1   C. 3.2   D. 2.0

The velocity ratio of a machine is 5 and its efficiency is 75%. What effort would be needed to lift a load of 150 N with the machine? (UTME 2000)

(a) 20 N     (b) 30 N    (c) 40 N     (d) 50 N

A block and tackle is used to raise a load of 250 N through a vertical distance of 30 m. What is the efficiency of the system if the work done against friction is 1500 J? (UTME 2012)

A. 62.5%    B. 73.3%   C. 83.3%   D. 94.3%

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

A plane inclined at 30° to the horizontal has an efficiency of 50%. Calculate the force parallel to the plane required to push a load of 120 N uniformly up the plane. (WASSCE 2007)

A. 50.0 N    B. 120.0 N    C. 200.0 N   D. 240.0 N