1. The problem statement, all variables and given/known data Hi, I'm fairly new to these forums and I'm stuck on a problem. Just wondered if anyone could give me any hints or tips on how to get started on the following question: An unstable particle produced in a high-energy collision has a mass of m and an uncertainty in mass that is p of the particle's mass. Estimate the liftime of the particle. 2. Relevant equations I am assuming this question has something to do with Heisenbergs Uncertainty Principle. i.e [tex] \Delta x*\Delta p >= \hbar [/tex] where p is momentum and x is some distance From the information given I assume I have to use the above formula to get: [tex] \Delta x*(p/m)*v >= \hbar [/tex] ....? where p/m is the uncertainty in the mass described in the question 3. The attempt at a solution As I said at the begining I don't really know how to get started on this question, and thus the derived relationship above is all I have managed to come up with thus far. I am begining to think that this question requires me to calculate the energy of the particle by calculating the minimum uncertainty on the momentum (i.e (p/m)*V). If the equation that I have formulated so far is correct, what am I supposed to use for delta x? From the information given I cannot see any way to deduce this. Any indication on whether im on the right lines here or any other help would be very much appreciated. Thanks in advance, Kam.