Moments - gears & levers

• What is a moment in physics?

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

  Moment equals force times distance.
• What is the common principle of levers and gears?

  • They transmit the turning effect of a force.
  • Input force creates an output force at a different point.
• What happens to the direction of forces when they are on different sides of the pivot?

  They act in different directions, one up and one down.
• What happens to the direction of forces when they are on the same side of the pivot?

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

  Because the output force is generally closer to the pivot than the input force.
• How much does a rock with a mass of 200 kg weigh in newtons?

  1960 newtons downwards.
• What is the formula to calculate weight from mass?

  Weight equals mass times gravitational field strength.
• What is the moment of the rock's weight if the distance from the pivot is 0.4 meters?

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

  It creates an anti-clockwise moment.
• What must be generated to lift the rock using a lever?

  A clockwise moment greater than 784 newton meters.
• If a person can only produce a 400 newton force, how far from the pivot must they apply that force to lift the rock?

  1.96 meters from the pivot.
• What is the role of gears in a system?

  Gears transmit turning effects.
• How do two interlocking gears affect each other’s rotation?

  Any rotation of one gear causes the other gear to rotate as well.
• In a gear system, how do the sizes of the gears affect the turning effect?

  The turning effect of the larger gear is greater than that of the smaller gear.
• How many times does gear A rotate for each rotation of gear B if gear B is twice the size of gear A?

  Gear A rotates two times for each rotation of gear B.
• What remains constant in a gear system despite the change in turning effect?

  The total work done remains the same.
• What is the main takeaway from the video regarding levers and gears?

  They both transmit the turning effect of a force.