A solid horizontal surface is covered with a thin layer of oil. A rectangular block of mass m = 0.4 kg is at rest on this surface. An impulse of 1.0 N s is applied to the block at time t = 0 so that it starts moving along the x-axis with a velocity v(t) = v₀e^(−t/τ), where v₀ is a constant and τ = 4 s. The displacement of the block, in metres, at t = τ is __________. Take e⁻¹ = 0.37.