The expression you've provided is \(10 + a^3\).
In this expression, the terms are:
- The first term is \(10\).
- The second term is \(a^3\).
The coefficient of the second term \(a^3\) is the number that multiplies \(a^3\). In this case, there is no number explicitly written before \(a^3\), which means the coefficient is \(1\).
Therefore, the coefficient of the second term \(a^3\) is \(1\).