🔍 Key Concepts

• Natural period of vibration of rotating machinery (like a shaft) • What happens when a machine’s running speed matches its natural frequency • The idea of resonance and how it affects machinery safety

💭 Think About

• Which term best describes the condition when a machine’s operating speed lines up with its own natural vibration frequency? • At what type of speed do vibrations usually become dangerously large if not controlled? • Which of these terms is most associated with engineers trying to avoid certain RPM ranges to prevent damage?

✅ Before You Answer

• Identify which option is linked to resonance or natural frequency in machinery textbooks or notes • Eliminate any terms that only describe how fast something can go (like maximum or design limits) rather than how it vibrates • Confirm which term is used when engineers specify RPM ranges that should be passed quickly or avoided due to high vibration