Practice test

Work, energy and power - Test Set 1

Review 20 exam-focused questions with detailed explanations, then start the interactive test when you are ready.

20 questions

Questions and explanations

  1. Question 1

    ……… is the rate of doing work.
    1. Velocity
    2. Energy
    3. Power
    4. Force
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  2. Question 2

    Name of the physical quantity which is equal to the product of force and velocity?
    1. Energy
    2. Power
    3. Acceleration
    4. Work
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  3. Question 3

    Which one of the following is the value of 1 kWh of energy converted into joules?
    1. 1.8 × 10^6 J
    2. 3.6 × 10^6 J
    3. 6.0 × 10^6 J
    4. 7.2 × 10^6 J
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  4. Question 4

    A boy of mass 50 kg runs up a staircase of 40 steps in 10 s. If the height of each step is 15 cm, find his power.
    1. 3375 W
    2. 300 W
    3. 300 ms
    4. 300 T
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  5. Question 5

    Work can only be done when there is:
    1. Momentum
    2. Energy
    3. Power
    4. Force
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  6. Question 6

    Which one of the following is not the unit of energy?
    1. J
    2. W-h
    3. N-m
    4. kg-m/s²
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  7. Question 7

    A car is moving with high speed. Which energy does it possess?
    1. Frictional force
    2. Gravitational force
    3. Kinetic energy
    4. Potential energy
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  8. Question 8

    If two unequal masses possess the same kinetic energy, then the heavier mass has:
    1. Lower speed
    2. Higher speed
    3. Lesser momentum
    4. Greater momentum
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  9. Question 9

    How is the kinetic energy of a moving object affected if the net work done on it is positive?
    1. Decreases
    2. Increases
    3. Remains constant
    4. Becomes zero
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  10. Question 10

    If the momentum of a body is doubled, the kinetic energy is:
    1. Becomes 1/4 times
    2. Unchanged
    3. Doubled
    4. Becomes 4 times
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  11. Question 11

    An object of mass 15 kg is moving with a uniform velocity of 7 ms⁻¹. What is the kinetic energy possessed by the object?
    1. 367.5 J
    2. 17.5 J
    3. 180.5 J
    4. 367.5 ms
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  12. Question 12

    Two objects A and B are moving with the same velocity. The mass of object A is twice that of B. The ratio of the kinetic energy of A to that of B. (K_A / K_B) will be:
    1. 4
    2. 2
    3. 1/2
    4. 1
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  13. Question 13

    The ratio of kinetic energies of two bodies of same mass 4 : 9. The ratio of their velocities will be:
    1. 4 : 9
    2. 2 : 3
    3. 16 : 81
    4. √2 : √3
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  14. Question 14

    Consider the following statements.
    I. There is no net moment on a body which is in equilibrium.
    II. The momentum of a body is always conserved.
    III. The kinetic energy of an object is always conserved.
    Which of the statements given above is/are correct?
    1. Only I
    2. II and III
    3. I and II
    4. All of these
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  15. Question 15

    Consider the following statements about Kinetic Energy (KE).
    I. If the mass of the body is made double, then its kinetic energy will become double.
    II. If either velocity or linear momentum of the body is double, its KE will become four times as that of original.
    Which of the statements given above is/are correct?
    1. Only I
    2. Only II
    3. Both I and II
    4. Neither I nor II
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  16. Question 16

    Assertion (A) If a light body and heavy body have equal kinetic energies, momentum is greater for the heavy body.
    Reason (R) If a light body and heavy body have same momentum, the light body will possess more kinetic energy.
    1. If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
    2. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
    3. Assertion is true but Reason is false.
    4. If both Assertion is false but Reason is true.
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  17. Question 17

    Assertion (A) The change in kinetic energy of a particle is equal to the work done on it by the net force.
    Reason (R) Change in kinetic energy of a particle is equal to the work done only in case of a system of one particle.
    1. If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
    2. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
    3. Assertion is true but Reason is false.
    4. If both Assertion is false but Reason is true.
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  18. Question 18

    A wound watch spring has …… energy.
    1. electrical
    2. kinetic
    3. potential
    4. Both kinetic and potential
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  19. Question 19

    A flying jet possesses ………
    1. potential energy
    2. kinetic energy
    3. wind energy
    4. Both kinetic and potential energy
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  20. Question 20

    A body rolling down on a hill has:
    1. kinetic energy only
    2. potential energy only
    3. only friction force
    4. Both kinetic energy and potential energy
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