Answer
1430 m/s.
Work Step by Step
Assume that the final kinetic energy of the meteorite is zero. Also, assume that the initial kinetic energy was used to heating the meteorite to its melting point, and then to melt the iron.
$$\frac{1}{2}mv_i^2=mc_{Fe}(T_{melt}-T_i)+mL_f$$
$$v_i=\sqrt{2(c_{Fe}(T_{melt}-T_i)+L_f)}$$
$$=\sqrt{2((450J/(kg\cdot C))(1538-(-105))+2.89\times10^5J/k)}=1430m/s$$
