The mass of Mr x is 50kg and the uncertainty in measurement is 1 kg.The mass of Mr y is 55kg and the uncertainty in measurement is 2 kg. Find the difference of their masses with correct uncertainties.
When you add or subtract observations the uncertainties get added.
Weight of X is 50 ± 1kg
Weight of Y is 55 ± 2kg
Difference in mass is 5kg (55-50)
Uncertainty is ± 3(1+2)
So difference in masses is 5 ± 3kg.