work, energy and power

• What is work done defined as?

  The product of force and distance
• What is the formula for work done in A-level physics?

  Work done = f x cosine(theta)
• What does the variable 'f' represent in the work done formula?

  Force applied
• What does the variable 'x' represent in the work done formula?

  Distance traveled
• What does 'theta' represent in the work done formula?

  Angle between force and displacement
• What should you do if given the angle complementary to theta?

  Subtract it from 90 degrees
• When is work done at a maximum?

  When theta is equal to zero degrees
• What is the cosine of zero degrees?

  1
• What happens to work done when the angle is 90 degrees?

  Work done is 0 joules
• What is the unit for work done?

  Joule
• What is the base unit of the joule?

  kg·m²/s²
• What does the principle of conservation of energy state?

  Energy cannot be created or destroyed
• What is the equation for change of energy in a system?

  Change of energy = work done
• What is the formula for potential energy?

  Potential energy = mgh
• What does 'm' represent in the potential energy formula?

  Mass of the object
• What does 'g' represent in the potential energy formula?

  Acceleration due to gravity
• What does 'h' represent in the potential energy formula?

  Height within a gravitational field
• How is work done related to potential energy when raising an object?

  Work done equals the change in potential energy
• What is the equation for kinetic energy derived from work done?

  Kinetic energy = 1/2 mv²
• What is the relationship between potential energy and kinetic energy when a ball rolls down a hill?

  Potential energy converts to kinetic energy
• What is the formula for speed derived from energy conservation?

  v = √(2gh)
• If a ball has a height of 5 meters, what is its speed at the bottom?

  v = √(2 × 9.81 × 5)
• What is the average resistive force acting on a ball rolling down a ramp?

  Force = change in energy / distance
• What is the equation for power?

  Power = work done / time
• How can power also be expressed in terms of velocity?

  Power = force × velocity
• How is mechanical efficiency calculated?

  Efficiency = (useful output energy / input energy) × 100
• What are the key concepts covered in this revision lesson?

  • Work done
  • Energy types (kinetic, potential)
  • Conservation of energy
  • Power and efficiency
• What are the relationships between work, energy, and power?

  • Work done is energy transferred
  • Energy can change forms (kinetic to potential)
  • Power is the rate of doing work