JAMB Physics questions: Work, energy and power

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

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

   A 0.5 kg ball is dropped from a height of 20 m. Find its speed just before it hits the ground. [g = 10 m/s²]

   • A10 m/s
   • B20 m/s
   • C200 m/s
   • D14 m/s

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

   A 2 kg body falls freely from a height of 20 m. Find its speed just before it hits the ground.

   • A20 m/s
   • B400 m/s
   • C10 m/s
   • D40 m/s

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

   A boy of mass 70 kg runs up a flight of stairs 3 m high in 7 s. Find his power.

   • A300 W
   • B30 W
   • C2100 W
   • D147 W

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

   A pump lifts 500 kg of water through a height of 12 m in 1 minute. Find its power output.

   • A1000 W
   • B60 000 W
   • C100 W
   • D6000 W

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

   An electric motor takes in 2000 W and gives out 1500 W of useful power. Find its efficiency.

   • A133%
   • B75%
   • C25%
   • D50%

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6. Question 6· 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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7. Question 7· 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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8. Question 8· 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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9. Question 9· 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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10. Question 10· 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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11. Question 11· 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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12. Question 12· 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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13. Question 13· 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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14. Question 14· 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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15. Question 15· 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

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