Simple Machines - Jamb Physics Past Questions and Answers

Question 21:

• JAMB 2001

The diagram above is a block and tackle pulley system in which an effort of 80N is use to lift a load of 240N. The efficiency of the machine is

A. 60%
B. 50%
C. 40%
D. 33%

Question 22:

• JAMB 2002

A wheel and axle is used to raise a load of 500 N by the application of an effort of 250 N. If the radii of the wheel and the axle are 0.4 cm and 0.1 cm respectively, the efficiency of the machine is

A. 20 %
B. 40 %
C. 50 %
D. 60 %

Question 23:

• JAMB 2004

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?

A. 1500N
B. 500N
C. 4166N
D. 750N

Question 24:

• JAMB 2005

In an ideal wheel an axle system, R stand for the radius of the wheel and r is the radius of the axle. the mechanical advantage is

A. (R/r)²
B. R/R
C. (r/R)²
D. R/r

Question 25:

• JAMB 2006

I. Work done by load is always less than the work done by effort.
II. All machines are made of levers, pulleys, screws and gear wheels.
III. A fishing rod is a machine.
Iv. Effort is always larger than load.
which of statements above about machines are true?

A. II and III
B. III and IV
C. I and III
D. II and iv