work done & energy transfer

• What should you be able to describe by the end of the video?

  What's meant by work done
• What happens when a force is used to move an object?

  Energy is transferred
• What is the equation to calculate work done?

  Work done (J) = Force (N) × Distance (m)
• Why must the distance be in the line of action of the force?

  To accurately calculate the work done
• What is the unit of work?

  The joule (J)
• How much work is done when a force of one newton moves an object by one meter?

  One joule of work is done
• What is the relationship between newton meters and joules?

  One newton meter of work 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 happens to the kinetic energy store of a car when it brakes?

  It is transferred to the thermal energy store of the brakes
• If a force of 3,000 newtons is applied to the brakes of a car over a distance of 15 meters, what is the work done?

  45,000 joules
• What is the effect of a person walking up a flight of stairs against the force of gravity?

  The person does work against their weight
• If a person has a weight of 600 newtons and moves vertically 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 type of energy store is involved when a person walks up stairs?

  Gravitational potential energy store
• What happens to a person's chemical energy store when they walk up stairs?

  It is transferred to the gravitational potential energy store
• What is the process of calculating work done when a force is applied?

  • Identify the force applied (in newtons)
  • Measure the distance moved (in meters)
  • Use the equation: Work done (J) = Force (N) × Distance (m)
• What are the key points to remember about work done in physics?

  • Work is a measure of energy transfer
  • The unit of work is the joule (J)
  • Distance must be in the line of action of the force
  • Work done against gravity involves vertical distance only