`s^(-1)` is the unit of_____

Explanation

To determine what `s^(-1)` is the unit of, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the notation**: The notation `s^(-1)` means "per second." This is a way to express a quantity that occurs or is measured in relation to time.

2. **Identifying the context**: In physics, we often deal with quantities that change over time. One common quantity that is expressed in terms of time is frequency.

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