It is not possible to know precisely the velocity and position of an electron at the same time. This is a fundamental principle in quantum mechanics known as the Heisenberg Uncertainty Principle.

Here's why:

* Wave-particle duality: Electrons exhibit both wave-like and particle-like properties. Their position and momentum are described by wave functions, which represent the probability of finding the electron at a particular location.

* Uncertainty: The wave function describes the probability distribution of the electron's position and momentum. The more precisely we know one, the less precisely we can know the other.

* Measurement: The act of measuring the electron's position inevitably disturbs its momentum, and vice versa. This disturbance is unavoidable and fundamental to the nature of quantum systems.

In summary:

* The Heisenberg Uncertainty Principle states that it is impossible to simultaneously know both the position and momentum (which includes velocity) of a particle with perfect accuracy.

* The more precisely we measure one, the less precisely we can measure the other.

* This is not a limitation of our measurement tools, but a fundamental property of quantum systems.

Therefore, it is not possible to know precisely the velocity and position of an electron at the same time.