  We analyse the dynamics of polymer translocation in the strong force regime
by recasting the problem into solving a differential equation with a moving
absorbing boundary. For the total translocation time, $\tau_{\rm tr}$, our
simple mean-field model predicts that $\tau_{\rm tr}\sim$ (number of
monomers)$^{1.5}$, which is in agreement with the exponent found in previous
simulation results. Our model also predicts intricate dependencies of
$\tau_{\rm tr}$ on the variations of the pulling force and of the temperature.
