Wheel on a Frictionless Axis A wheel of radius $0.20 \mathrm{~m}$ is mounted on a frictionless horizontal axis. The rotational inertia of the wheel about the axis is $0.050 \mathrm{~kg} \cdot \mathrm{m}^{2} .$ A massless cord wrapped around the wheel is attached to a $2.0 \mathrm{~kg}$ block that slides on a horizontal frictionless surface. If a horizontal force of magnitude $P=$ $3.0 \mathrm{~N}$ is applied to the block as shown in Fig. $11-35$, what is the magnitude of the rotational acceleration of the wheel? Assume that the string does not slip on the wheel.