Final answer:
A moving object in dynamic equilibrium with no net force will maintain its speed of 3 m/s after 10 seconds due to Newton's first law of motion.
Step-by-step explanation:
An object moving at 3 m/s and in dynamic equilibrium implies that there are no net external forces acting on it. According to Newton's first law of motion, an object at rest or moving with constant velocity will continue to do so unless acted upon by a net external force. Since the object experiences no net force, it will maintain its state of motion. Therefore, the speed of the object 10 seconds later will be the same as its initial speed, 3 m/s.