work done and energy transfer

• What happens when a man pushes a box at constant velocity?

  The box experiences friction and temperature increase
• What energy transfer occurs when a man pushes a box?

  Chemical energy to thermal energy
• What is the definition of work in scientific terms?

  Energy transferred by a force moving an object
• How do you calculate work done?

  Work done = force × distance
• What is the unit of work?

  Joule
• What does one Joule of work represent?

  One Newton moving an object by one meter
• What is the relationship between Newton meters and Joules?

  One Newton meter equals one Joule
• If a man applies a force of 20 Newtons to move a box by 2 meters, what is the work done?

  40 Joules
• What is the work done when a force of 3,000 Newtons is applied over a distance of 15 meters?

  45,000 Joules
• What happens to the kinetic energy of a car when it brakes?

  Kinetic energy is transferred to thermal energy
• What force acts between the brake and the wheel during braking?

  Friction
• How is work done calculated when moving up stairs?

  Work done = weight × vertical distance
• If a person with a weight of 600 Newtons moves up 5 meters, what is the work done?

  3,000 Joules
• Why is only the vertical distance relevant when calculating work done against gravity?

  Because weight acts vertically downwards
• What is transferred from a person's chemical energy store when climbing stairs?

  Gravitational potential energy
• What are the key points about work done in physics?

  • Work done is energy transfer by force
  • Calculated as work = force × distance
  • Unit of work is Joule (J)
  • Distance must align with the force direction