The concept you're referring to is known as the principle of uncertainty or Heisenberg's uncertainty principle, which arises from the field of quantum mechanics. According to this principle, there are inherent limits to the precision with which certain pairs of physical properties, such as position and velocity, can be simultaneously measured.
The uncertainty principle states that the more precisely you try to measure the position of a particle, the less precisely you can know its momentum (which is related to velocity), and vice versa. In other words, the more accurately you determine the position of an object, the more uncertain its velocity becomes, and vice versa.
This does not mean that an object can physically exist in two places at once. Rather, it reflects the fundamental nature of particles on a microscopic scale, where their behavior is described by wave-like properties and probabilities. Until a measurement is made, a particle can be in a superposition of states, meaning it can exist in multiple states or locations simultaneously. However, upon measurement, the particle's properties "collapse" into a specific value or location.
So, in practice, we cannot measure both the position and velocity of a particle with absolute precision at the same time. The uncertainty principle sets a fundamental limit on the precision of such simultaneous measurements. The more accurately you measure one property, the less accurate your measurement of the other property becomes.
It's important to note that the uncertainty principle applies to the microscopic world of quantum mechanics and is not noticeable in everyday life or macroscopic objects, where classical physics is sufficient for most purposes.