Chapter 3 Lesson 3

A(n) _____ is a machine that does work using only one movement.

• wheel
• pulley
• screw
• simple machine

These machines do work in a(n) _____ motion.

1. A(n) _____ is a simple machine made of a bar that pivots or rotates about a fixed

   point.

• lever
• wheel
• pulley
• screwdriver

1. The point that a lever pivots on is called a(n) _____.

• center
• base
• pivot
• fulcrum

1. The distance from the fulcrum to the input force is the _____; the distance from the fulcrum to the output force is the _____.

• 1. input arm

• right arm

• left arm

• 1. output arm

1. With a first-class lever, the fulcrum is _____ the input force and the output force.

1. With a second-class lever, the _____ force is between the _____ force and the

   fulcrum.

• 1. output

• lever

• 1. input

• machine

1. With a third-class lever, the _____ force is between the _____ force and the fulcrum.

1. The ideal _____ of a lever equals the length of the input arm divided by the length of the output arm.

• mechanical disadvantage
• fulcrum position
• load force
• mechanical advantage

The mechanical advantage of a(n) _____-class lever can vary, depending on the location of the fulcrum.

• third
• first
• fourth
• second