Work , Power and Energy questions with solutions

Showing 1–10 of 128 questions

• A/RmediumWork , Power and EnergyPower

  Evaluate the following statements.

  Assertion

  Assertion (A): For a car driven by an engine of constant power on a resistance-free horizontal road, acceleration decreases as speed increases.

  Reason

  Reason (R): At constant power, the driving force is inversely proportional to speed.

  Options

  • Option A

    Both A and R are true and R is the correct explanation of A.

  • Option B

    Both A and R are true but R is NOT the correct explanation of A.

  • Option C

    A is true but R is false.

  • Option D

    A is false but R is true.

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• MCQeasyWork , Power and Energyquestion based on work

  A body of mass 50 kg is lifted to a height of 20 m from the ground in the two different ways as shown in the figures. The ratio of work done against the gravity in both the respective cases, will be:

  

  Options

  • Option A

    1 : 1

  • Option B

    2 : 1

  • Option C

    √3 : 2

  • Option D

    1 : 2

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  JEE Mains 2024 05 Apr Morning Shift

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• Multi-correctmediumWork , Power and Energyconservation of mechanical energy

  A particle moves from A to B under conservative and non-conservative forces. Which statements are correct?

  Select all that apply

  • Option A

    Δ(K+U) = $W_nc$

  • Option B

    If $W_nc$ = 0, mechanical energy is conserved

  • Option C

    If friction does negative work, mechanical energy generally decreases

  • Option D

    Mechanical energy can increase due to positive work by an external non-conservative force

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• IntegereasyWork , Power and Energyquestion based on work

  A force F = (2 + 3x) î N acts along the x-direction. Find the work done from x = 0 to x = 4 m.

  Your answer

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  JEE Mains11 April 2023Shift 1Morning Shift

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• MCQeasyWork , Power and Energykinetic enegy and work engery theorem

  Four particles A, B, C, D of mass m/2, m, 2m, 4m, have same momentum, respectively. The particle with maximum kinetic energy is :

  Options

  • Option A

    D

  • Option B

    C

  • Option C

    A

  • Option D

    B

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  JEE Mains 2024 06 Apr Morning Shift

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• NumericmediumWork , Power and Energyconservation of mechanical energy

  A 2 kg block is released from rest from a height of 0.9 m above a smooth horizontal surface. It then compresses an initially uncompressed spring of force constant 400 N/m. If the maximum compression is N/10 m, find N. Take g = 10 m/s².

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• Multi-correcteasyWork , Power and Energyquestion based on work

  For a constant force F acting on a particle between two positions, which statements are correct?

  Select all that apply

  • Option A

    Work equals F·Δr and depends only on the endpoints

  • Option B

    Work can be zero even for non-zero displacement

  • Option C

    Work can be negative

  • Option D

    If the particle returns to its initial position, net work by this constant force is zero

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• MCQeasyWork , Power and Energykinetic enegy and work engery theorem

  A bullet of mass 50 g is fired with a speed 100 m/s on a plywood and emerges with 40 m/s. The percentage loss of kinetic energy is :

  Options

  • Option A

    32%

  • Option B

    44%

  • Option C

    16%

  • Option D

    84%

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  JEE Mains 2024 06 Apr Morning Shift

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• NumericmediumWork , Power and Energyconservation of mechanical energy

  A 1 kg block is dropped from a point 1.2 m above an initially uncompressed vertical spring of force constant 200 N/m. Take g = 10 m/s². If the maximum compression is N/10 m, find N.

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• MCQeasyWork , Power and Energyquestion based on work

  A particle moves from x = 0 to x = 4 m under the force F(x) = 12 - 6x N. Total work done by this force is:

  Options

  • Option A

    -24 J

  • Option B

    0

  • Option C

    24 J

  • Option D

    48 J

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