Work, Energy and Power - Jamb Physics Past Questions and Answers

Question 26:

• JAMB 2009

If a cage containing a truck of coal weighing 750 kg is raised to a height of 90 m in a minute, what is the total power expended?
[g = 10 ms²]

A. 11.50 kw
B. 12.60 kw
C. 11.25 kw
D. 12.10 kw

Question 27:

• JAMB 2012

A car of mass 800kg attains a speed of 25m/s in 20 secs. The power developed in the engine is

A. 1 . 25 x 10⁴ W
B. 2 . 50 x 10⁴ W
C. 1 . 25 x 10⁶W
D. 2 . 50 x 10⁶ W

Question 28:

• JAMB 2012

If the force and the velocity on a system are each reduced simultaneously by half, the power of the system is

A. Doubled
B. Reduced to a quarter
C. Reduced by half
D. Constant

Question 29:

• JAMB 2012

A stone of mass 1kg is dropped from a height of 10m above the ground and falls freely under gravity. Its kinetic energy 5m above the ground is then equal to

A. Its kinetic energy on the ground
B. Twice its initial potential energy
C. Its initial potential energy
D. Half its initial potential energy

Question 30:

• JAMB 2012

A gas with initial volume of 2 X 10^-6m³ is allowed to expand to six times its initial value at constant pressure of 2 x 10⁵Nm^-2. The work done is

A. 2.0J
B. 4. 0 J
C. 12.0 J
D. 2.4 J