The setting is the following: Mr. Leonelli lives in quantumland where h = 100 [Js]. His mass is m = 80 kg, his speed is v = 1.1 m/s. Can Mr. Leonelli rest in his seat?(adsbygoogle = window.adsbygoogle || []).push({});

We're confused about the meaning of the uncertainty relation, in light of the fact that we're told that his speed is 1.1 and his mass is 80. So his momentum is 88. Right there, without even considering quantum effects, we can tell that he cannot be AT REST in his seat.

On the other hand, we understand that if we know him to be in his seat, then [itex]\Delta x = 0[/itex], so [itex]\Delta p = \infty[/itex], but we believe that this does not mean that the uncertainty on p IN THE SENSE OF classical laboratory data is infinite. We think it only means that his momentum is undefined, or rather, spread out over an infinite margin, such that for a given measure on it, it can be anything. Again, this would contradict the fact that the setting of the problem states p=88.

Any thruth in those words or are we off track?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Easy QM uncertainty question

**Physics Forums | Science Articles, Homework Help, Discussion**