Chapter 12 review


    Vocabulary
    Match each word to the sentence where it best fits.
      Section 12.1

      fulcrum input arm
      input force lever
      machine mechanical advantage
      output arm output force
      simple machine 
      1. When a wedge is pounded into a log using a sledgehammer, the sledgehammer provides the _______.
      2. The ramp, screw, and lever are each a different kind of _______.
      3. The ratio of the output force to the input force is called the _______.
      4. When you use a crowbar to remove a nail from a piece of wood, the distance from the crowbar’s pivot point to the nail is the _______.
      5. A tricycle is a/an _______, because its drive train changes the magnitude and direction of a force.
      6. The balance point for a see-saw is called its _______.
      7. When a person turns the wheel of a wheel and axle system, the axle delivers the _______.
      8. A rigid object that rotates about its fulcrum is called a/an _______.
      Section 12.2

      block and tackle efficiency
      gear gear ratio
      ideal mechanical advantage pulley
      tension wheel and axle
      1. A rope and pulley system that uses more than one pulley is called a/an _______.
      2. The gear and rear tire of a bicycle is an example of a _______.
      3. A wheel with 24 teeth was turned, causing a wheel with 8 teeth to turn. The system has a/an _______ of three.
      4. A toothed wheel is called a/an _______.
      5. The ratio of the radius of a wheel to the radius of its axle is the _______ of that wheel-and-axle system.
      1. During a tug-of-war competition, the _______ is the force exerted by the two teams along the rope.
      2. Real-world machines generate less output force than ideal machines because the _______ is usually less than 100%.
      Section 12.3

      impulse ramp
      screw wedge
      1. The switchbacks of a trail up the side of a mountain are an example of a/an _______.
      2. A triangular doorstop placed partially under a door to keep it open is an example of a/an _______.
      3. When you turn a/an _______, it converts the rotational motion into translational motion into the material.
      Section 12.4

      biomechanics compound machine
      microphone 
      1. A device that combines a lever, pulley, and screw is an example of a _______.
      2. _______ is the field of science to study how various parts of the body move.
      Conceptual questions
        Section 12.1
          Crowbar, board, and nail
        1. The diagram shows three pairs of action–reaction forces acting between a crowbar, a board, a nail, and a hand (not shown) pushing the right end of the crowbar. Consider the crowbar as a simple machine (lever).
          1. Which force is the input force on the lever and which is the output force?
          2. Where is the fulcrum located?
        2. What is the difference between a simple and compound machine?
        3. Define mechanical advantage in your own words.
        4. Name four simple machines.

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