Work, Potential and Kinetic Energy

Work, Potential, and Kinetic Energy

Objectives

• Define work in physics.
• Differentiate:
  • Potential energy from kinetic energy
  • Gravitational potential energy from elastic potential energy
• Apply the equation of work and energy in solving problems.
• Appreciate the importance of work and energy in daily life.

Introduction to Work

• Everyday activities often lead to tiredness, whether through play or work.
• Some activities cause tiredness without significant physical exertion.

Examples of Work Done in Physics

• Change in Position or Displacement:
  • A man pushing a box from location A to location B.
  • A lady lifting a sack from the ground overhead.
• Change in Speed or Direction:
  • A boy hitting a ball in a football match.
  • A crane towing a broken car to a workshop.
  • A batsman hitting a ball during a cricket match.
• Change in Shape or Size:
  • Kids making shapes with plasticine.
  • A compressed spring releasing a ball.

When is Work Done?

• Work Done: Object moves in the direction of the force.
• No Work Done:
  • No movement occurs.
  • The direction of the force and movement are different.

Definition of Work

• Work is the force necessary to move an object a distance.
• Examples of work:
  • Crane lifting an object
  • Weight-lifter lifting weights
  • Model train moving
  • Person pushing a barrow

Work in Physics

• Mechanical work is the amount of energy transferred by a force acting through a distance.
• It is a scalar quantity measured in joules (J).
• The term