A string is wrapped around the rim of a wheel of moment of inertia \( 0.40 \, \text{kg m}^{2} \) and radius \( 10 \, \text{cm} \). The wheel is free to rotate about its axis. Initially the wheel is at rest. The string is now pulled by a force of \( 40 \, \text{N} \). The angular velocity of the wheel after \( 10 \, \text{s} \) is \( x \, \text{rad/s} \), where \( x \) is _______.
