3-1 What is a simple machine?
OBJECTIVE: Describe how machines make work easier.
Key Terms
machine: device that makes work easier
wheel and axle: two different-sized wheels that turn together around the same point
effort force: force applied to a machine
resistance force: force that opposes the effort force
mechanical advantage: number of times a machine multiplies the effort force
ideal mechanical advantage: mechanical advantage a machine would have if there were no friction
Lesson Summary
• Machines make work easier by changing the size, direction, or speed of a force.
• Most machines are made up of two or more of these six simple machines: the lever, the pulley, the inclined plane, the wedge, the screw, and the wheel and axle.
• The force you apply to a machine is called the effort force. The force that opposes the effort force is the resistance force.
• The number of times a machine multiplies effort force is the machine’s mechanical advantage, or MA. Mechanical advantage is equal to resistance force divided by effort force.
• Because of friction, the actual mechanical advantage of a machine is less than the ideal mechanical advantage.
Key Terms
machine: device that makes work easier
wheel and axle: two different-sized wheels that turn together around the same point
effort force: force applied to a machine
resistance force: force that opposes the effort force
mechanical advantage: number of times a machine multiplies the effort force
ideal mechanical advantage: mechanical advantage a machine would have if there were no friction
Lesson Summary
• Machines make work easier by changing the size, direction, or speed of a force.
• Most machines are made up of two or more of these six simple machines: the lever, the pulley, the inclined plane, the wedge, the screw, and the wheel and axle.
• The force you apply to a machine is called the effort force. The force that opposes the effort force is the resistance force.
• The number of times a machine multiplies effort force is the machine’s mechanical advantage, or MA. Mechanical advantage is equal to resistance force divided by effort force.
• Because of friction, the actual mechanical advantage of a machine is less than the ideal mechanical advantage.