A bullet of mass \( 200\,\text{g} \) having initial kinetic energy \( 90\,\text{J} \) is shot inside a long swimming pool as shown in the figure. If it’s kinetic energy reduces to \( 40\,\text{J} \) within \( 1\,\text{s} \), the minimum length of the pool, the bullet has to travel so that it completely comes to rest is:
