Simple Machines - Jamb Physics Past Questions and Answers

Question 31:

• JAMB 2011

A machine is used to lift a load of 20 N through a height of 10 m. if the efficiency of the machine is 40%, how much work is done?

A. 80 J
B. 500 J
C. 300 J
D. 120 J

Question 32:

• JAMB 2012

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

A. 20N
B. 30N
C. 40N
D. 50N

Question 33:

• JAMB 2012

The efficiency of a machine is always less than 100% because the

A. Work output is always greater than the work input
B. Load lifted is always greater than the effort applied
C. Effort applied is always greater than the load lifted
D. Velocity ratio is always greater than the mechanical advantage

Question 34:

• JAMB 2012

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 35:

• JAMB 2013

What effort will a machine of efficiency 90% apply to lift a load of 180N if its efforts arm is twice as long as its load arm?

A. 80N
B. 90N
C. 100N
D. 120N