Moments - gears and levers

• 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
• How do input and output forces behave in scissors?

  They act in different directions
• How do input and output forces behave in a wheelbarrow?

  They act in the same direction
• Why is the output force generally larger in levers?

  It is closer to the pivot than 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 = 1960 times 0.4
• What is the moment of the rock's weight if the distance is 0.4 m?

  784 newton meters
• What must be generated to lift the rock?

  A clockwise moment greater than 784 newton meters
• If you can produce a 400 newton force, how far from the pivot must you push?

  More than 1.96 meters
• What role do gears play in machines?

  Transmit turning effects
• How does a gear system work in a car?

  • Gear A connected to the engine
  • Gear B connected to the wheels
  • Rotation of Gear A causes Gear B to rotate
  • Transmits engine's turning effect to wheels
• How do the gears rotate in a gear system?

  In opposite directions
• How does the size of gears affect their turning effect?

  Gear B's turning effect is twice Gear A's
• How many times does Gear A rotate for each rotation of Gear B?

  Two times
• What happens to the total work done in the gear system?

  It remains the same