Quantum mechanics is the study of motion of lighter particles, such as electron. Before establishment of quantum mechanics once the entire physics was based on classical mechanics which is also known as Newtonian classical mechanics.
But Newtonian classical mechanics was only concentrated into explaining the behavior of motion of massive objects, and it fails to explain the behavior of motion of massive object. It fails to explain the behavior of speed of light.
But Newtonian classical mechanics was only concentrated into explaining the behavior of motion of massive objects, and it fails to explain the behavior of motion of massive object. It fails to explain the behavior of speed of light.