What would be the uncertainty in velocity (miles/hr) of a neutron beam particle if the position can be measured within +/- 25 angstroms.

The rest mass of a neutron = 1.67493 X 10^-27 kg or 1.008664904(14) amu.

I know you have to use the heisenberg uncertainty principle: (deltaX)(delta mv) > (or equal to) planck's constant/4pi.

So far I have (+/- 25 A)(1.67493XX 10^-27 kg) > 5.21X10^-34

what do i do now?

2 answers

I believe you must convert Angstroms to meters.
h = 6.626 x 10^-34 J.s instead of the 5.21 you have. Then solve the equation and convert m/s you get for the answer to mi/hr
Also, consider that the uncertainty is +/- 25 and the total "swing" is 50 Ao.Check my thinking.