Answer:
Speed of the railroad car is equal to 1.664 m/sec
Step-by-step explanation:
We have given mass of the car

Spring constant of the spring

Spring is stretched by 36 cm
So x = 36 cm = 0.36 m
Work done by spring is equal to

This energy will be equal to kinetic energy of the car
So




v = 1.664 m/sec
Sp speed of the railroad car is equal to 1.664 m/sec