An empty train car of mass 2500 kg traveling at 5.0 m/s passes beneath a spigot that dumps 350 kg of sand into the car. Ignoring friction between the car and the track, determine the speed of the car after the sand was dumped.
a) Cannot be determined without more information.
b) 1.7 m/s
c) 15 m/s
d) 3.7 m/s