173. An oscillator with mass $100\,\text{g}$ is attached to a spring with spring constant $40\,\dfrac{\text{N}}{\text{m}}$, placed on a horizontal surface, and performs simple harmonic motion without friction. If the total mechanical energy of the oscillator equals $8\,\text{mJ}$, and the mechanical energy of the oscillator equals the tangential kinetic energy, what is the speed of the oscillator at that moment (in meters per second)? $$\frac{\sqrt{2}}{10} \;(1) \qquad \frac{\sqrt{2}}{5} \;(2) \qquad 10\sqrt{2} \;(3) \qquad 20\sqrt{2} \;(4)$$
\textbf{173.} An oscillator with mass $100\,\text{g}$ is attached to a spring with spring constant $40\,\dfrac{\text{N}}{\text{m}}$, placed on a horizontal surface, and performs simple harmonic motion without friction. If the total mechanical energy of the oscillator equals $8\,\text{mJ}$, and the mechanical energy of the oscillator equals the tangential kinetic energy, what is the speed of the oscillator at that moment (in meters per second)?
$$\frac{\sqrt{2}}{10} \;(1) \qquad \frac{\sqrt{2}}{5} \;(2) \qquad 10\sqrt{2} \;(3) \qquad 20\sqrt{2} \;(4)$$