Final answer:
The speed limit for objects with mass is that they can only approach, but never reach or exceed, the speed of light, which is about 299,792,458 m/s in a vacuum.
Step-by-step explanation:
The speed of light is the ultimate speed limit for any particle having mass, which is approximately 299,792,458 meters per second (m/s) in a vacuum. For objects with mass, this speed is unattainable, no matter how much energy you invest to accelerate them.
As per Einstein's theory of relativity, as the speed of an object with mass approaches the speed of light, its mass effectively becomes infinite, and it would require an infinite amount of energy to accelerate it to the speed of light. Therefore, the speed limit for things with mass is not a fixed number like 299,792,457 m/s, but rather it's that they can only asymptotically approach, but never reach or exceed, the speed of light.
The speed of light, which is approximately 299,792,458 meters per second, is the ultimate speed limit for any particle that has mass. This means that no matter how much energy is put into accelerating a mass, its velocity can only approach, but never reach, the speed of light. So, the speed limit for things with mass is indeed 299,792,458 m/s, the same as the speed of light.