(a) Work, Energy and Power - Jamb Physics Past Questions and Answers

Question 21:

• JAMB 1990

A stone of mass m kg is held h meters above the floor for 50s. The work done in joules over this period is

A. Mh
B. Mgh
C. \(\frac{mgh}{50}\)
D. O

Question 22:

• JAMB 1991

A body is under action of a force F such that the force displacement graph of the body is semi circular as shown above. The work done on the body by the force in moving through 24 meters is

A. 36Ï€ J
B. 72π J
C. 144Ï€ J
D. 288Ï€ J

Question 23:

• JAMB 1992

A man weight 800N climbs up a stairs to height of 15m in 12.5s. What is the man''s average power output?

A. 667W
B. 810W
C. 960W
D. 15000W

Question 24:

• JAMB 1993

Which of the following correctly describes the energy changes in the generation of light by a hydroelectric power station?

A. Electrical \(\to\) mechanical \(\to\) potential
B. Potential \(\to\)mechanical \(\to\)electrical \(\to\) light
C. Mechanical \(\to\) sound \(\to\) electrical \(\to\) light
D. Kinetic \(\to\) mechanical \(\to\) electrical \(\to\)light

Question 25:

• JAMB 1994

An object of mass 50kg is released from a height of 2m.Find the kinetic energy just before it strikes the ground

A. 250J
B. 1000J
C. 10 000J
D. 100 000J