The characteristic that will be affected by increasing the speed of an object from 30 meters per second to 40 meters per second is kinetic energy.
Kinetic energy is calculated using the formula:
\[ \text{Kinetic Energy} (KE) = \frac{1}{2}mv^2 \]
where \( m \) is the mass of the object and \( v \) is its velocity. As the velocity increases, the kinetic energy increases with the square of the velocity.
So, the correct answer is:
O kinetic energy.