Moments, levers and gears

• What is a moment in physics?

  The turning effect of a force
• How is the moment calculated?

  Moment equals force times distance
• What is the principle of levers?

  • Transmit the turning effect of a force
  • Input force creates an output force
  • Input and output forces can act in different directions
• What happens when input and output forces are on different sides of the pivot?

  They act in different directions
• What happens when input and output forces are on the same side of the pivot?

  They act in the same direction
• Where is the output force generally located in relation to the pivot?

  Closer to the pivot than the input force
• What is the advantage of using levers?

  To get a large output force with a small input force
• What is the weight of a rock with a mass of 200 kg?

  1960 newtons downwards
• How do you calculate the moment of the rock's weight?

  Moment = weight times distance
• What is the moment of the rock's weight if the distance is 0.4 meters?

  784 newton meters
• What direction is the moment of the rock's weight around the pivot?

  Anti-clockwise moment
• What must be generated to lift the rock?

  A clockwise moment greater than 784 newton meters
• If the maximum force we can apply is 400 newtons, how far from the pivot must we push?

  1. 96 meters
• What is the role of gears in a system?

  To transmit turning effects
• How do gears interact in a system?

  • Gear A connected to the engine
  • Gear B connected to the wheels
  • Rotation of Gear A causes Gear B to rotate
• In which direction do the gears turn in a gear system?

  In opposite directions
• How does the size of Gear B compare to Gear A?

  Gear B's radius is two times larger
• What is the effect of Gear B being larger than Gear A?

  The turning effect of Gear B is doubled
• How many times does Gear A rotate for each rotation of Gear B?

  Two times
• What remains the same despite the gear size difference?

  The total work done remains the same