3-2 What is efficiency?
OBJECTIVE: Explain how to find the efficiency of a machine.
Key Terms
work output: work done by a machine
work input: work done on a machine
efficiency: ratio of work output to work input
Lesson Summary
• Work output is equal to the resistance force times the distance over which the resistance force acts.
• Work input is equal to the effort force times the distance over which the effort force acts.
• The efficiency of a machine is the ratio of work output to work input.
• Efficiency is usually expressed as a percentage.
Key Terms
work output: work done by a machine
work input: work done on a machine
efficiency: ratio of work output to work input
Lesson Summary
• Work output is equal to the resistance force times the distance over which the resistance force acts.
• Work input is equal to the effort force times the distance over which the effort force acts.
• The efficiency of a machine is the ratio of work output to work input.
• Efficiency is usually expressed as a percentage.