Work and Energy

    Cards (13)

    • Work requires energy
    • Work is done when a force produces motion in a body
    • Conditions for work to be done:
      • Force should be applied on the body
      • Body should be displaced
    • Work done in moving a body = Force × Displacement
      Work is a scalar quantity
    • Unit of work is Newton meter or Joule
      1 Joule = 1 Newton × 1 meter
    • Factors affecting the amount of work done:
      • Magnitude of force
      • Displacement
    • Work done by a force can be positive, negative, or zero
      • Positive work: force acts in the direction of motion
      • Negative work: force acts opposite to the direction of motion
      • Zero work: force acts at right angles to the direction of motion
    • Energy is the capacity of doing work
    • Energy is a scalar quantity
      SI unit of energy is Joule (J)
    • Mechanical energy is the sum of kinetic energy and potential energy of a body
    • Kinetic energy is the energy of a body due to its motion
      • Kinetic energy is directly proportional to mass and the square of velocity
    • Potential energy is the energy of a body due to its position or change in shape
    • Unit of power:
      • SI unit of power is Watt (W) = 1 Joule/second
      • 1 Watt (W) = 1 Joule / 1 second = 1 J / 1 s
      • Average power = Total work done or total energy used / Total time taken
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