JAMB Physics questions

450 questions with answers and explanations. Tap an option to check yourself.

1. Question 441· Work, energy and power· JAMB

   A 2 kg stone falls freely from a height of 5 m. Find its kinetic energy just before it hits the ground.

   • A50 J
   • B10 J
   • C100 J
   • D200 J

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   Answer: C. 100 J

   Explanation and discussion

2. Question 442· Work, energy and power· JAMB

   A machine lifts a 100 kg load through 4 m in 20 s. Its power output is: (g = 10 m/s²)

   • A20 W
   • B400 W
   • C200 W
   • D2000 W

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   Answer: C. 200 W

   Explanation and discussion

3. Question 443· Work, energy and power· JAMB

   A force of 20 N moves a body through 5 m in the direction of the force. The work done is:

   • A4 J
   • B100 J
   • C25 J
   • D15 J

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   Answer: B. 100 J

   Explanation and discussion

4. Question 444· Work, energy and power· JAMB

   One kilowatt-hour is equal to

   • A3.6 × 10³ kJ per second
   • B1000 J
   • C3600 J
   • D3.6 × 10⁶ J

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   Answer: D. 3.6 × 10⁶ J

   Explanation and discussion

5. Question 445· Work, energy and power· JAMB

   A machine does 4,000 J of useful work when 5,000 J of energy is supplied. Its efficiency is

   • A80%
   • B125%
   • C20%
   • D1,000%

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   Answer: A. 80%

   Explanation and discussion

6. Question 446· Work, energy and power· JAMB

   A 60 kg boy runs up a staircase 12 m high in 30 s. Find his power. [g = 10 m/s²]

   • A7,200 W
   • B240 W
   • C24 W
   • D2,400 W

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   Answer: B. 240 W

   Explanation and discussion

7. Question 447· Work, energy and power· JAMB

   A 2 kg body moving at 3 m/s has kinetic energy of:

   • A9 J
   • B6 J
   • C3 J
   • D18 J

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   Answer: A. 9 J

   Explanation and discussion

8. Question 448· Work, energy and power· JAMB

   A car of mass 1000 kg speeds up from 10 m/s to 20 m/s. Find the work done on it.

   • A1.5 × 10⁵ J
   • B5 × 10⁴ J
   • C2 × 10⁵ J
   • D1 × 10⁴ J

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   Answer: A. 1.5 × 10⁵ J

   Explanation and discussion

9. Question 449· Work, energy and power· JAMB

   For a swinging pendulum, the kinetic energy is greatest at the

   • Apoint of release
   • Bhighest point of the swing
   • Clowest point of the swing
   • Dmiddle of the string

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   Answer: C. lowest point of the swing

   Explanation and discussion

10. Question 450· Work, energy and power· JAMB

    A 5 kg mass is raised through 4 m. Find its gain in potential energy.

    • A20 J
    • B200 J
    • C2000 J
    • D9 J

    Show answer

    Answer: B. 200 J

    Explanation and discussion