Final answer:
Einstein's postulates imply time dilation and length contraction which contradict the absolute time and space concepts in Newton's laws of motion, making scenarios where speeds close to the speed of light result in outcomes divergent from classical mechanics.
Step-by-step explanation:
The two postulates of Einstein's theory of special relativity address the invariance of the laws of physics in inertial frames and the constancy of the speed of light, irrespective of observer motion. When combined, these postulates can lead to predictions that appear inconsistent with Newton's laws of motion and the mechanics of classical physics. One such inconsistency arises with time dilation and length contraction. For instance, as an object approaches the speed of light, time as measured by a stationary observer will seem to slow down for the moving object (time dilation), while the object itself will appear shorter along the direction of motion (length contraction). These effects contradict Newtonian physics, which implies that absolute time and space are a backdrop through which objects move.
Moreover, the relativistic addition of velocities does not follow the simple arithmetic addition assumed by classical mechanics. Instead, speeds add together in such a way that the resultant speed never exceeds the speed of light. In a Newtonian framework, speeds would simply add, leading to potential velocities greater than the speed of light, which contradicts the special theory of relativity.