A solid horizontal surface is covered with a thin layer of oil. A rectangular block of mass $m=0.4 \mathrm{~kg}$ is at rest on this surface. An impulse of 1.0 Ns is applied to the block at time $t=0$ so that it starts moving along the x -axis with a velocity $\mathrm{v}(\mathrm{t})=\mathrm{v}_0 \mathrm{e}^{-t / \tau}$, where $\mathrm{v}_0$ is a constant and $\tau=4 \mathrm{~s}$. The displacement of the block, in meters, at $\mathrm{t}=\tau$ is $\_\_\_\_$ Take $\mathrm{e}^{-1}=0.37$.