# A tall building sways in the wind. Engineers design the building so that its natural frequency of oscillation is very different from the typical frequency of wind gusts. Explain why this design feature is important, and describe what would happen if the two frequencies were equal.

> AQA A-Level Physics (7408) — 3.6.1 Periodic Motion · Explain · 5 marks

## Mark scheme (5 marks)

1. The building has a natural frequency at which it oscillates freely / when undamped
2. Wind gusts act as a periodic driving force / the wind applies a driving frequency to the building
3. If the driving frequency equals the natural frequency, resonance occurs
4. At resonance the amplitude of oscillation increases greatly / the building oscillates with maximum amplitude
5. This could cause structural damage to / collapse of the building, so keeping frequencies different prevents resonance

## Key terms

- [natural frequency](https://www.gradenine.co.uk/glossary/natural-frequency)

## Related

- [Revision notes for AQA A-Level Physics (7408)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-tall-building-sways-in-the-4b168b61) · Published by Druglandscape Ltd.