1. The problem statement, all variables and given/known data A small flat circular disc of diameter 2mm and mass 5mg is lowered vertically to rest at the centre of a flat tray of width 10mm in the x direction and 50mm in the y direction. What is the minimum uncertainty in measuring the velocity of the particle in the x direction? Considering possible motion only in the x direction, determine whether it is likely that the disc would touch the side of the tray in a given time: (a) overnight (b) in the lifetime of the Universe (approx. 15 billion years) 2. Relevant equations The only equation I can muster up is Heisenberg's [tex]\Delta[/tex]x[tex]\Delta[/tex]p ~ h 3. The attempt at a solution I have no idea how to go about this one. Not sure I understand the problem at all. Please help.