A \( 12\,600 \) \( \text{kg} \) railroad car travels alone on a level frictionless track with a constant speed of \( 18.0 \) \( \text{m/s} \). A \( 5350 \) \( \text{kg} \) load, initially at rest, is dropped onto the car. What will be the car’s new speed?

Figure 1. A railroad car moving on a track before and after a load is dropped onto it.