Question

The mass of a box measured by a grocer's balance is 2.3 kg. Two gold pieces of masses 20.15 g and 20.17g are added to the box. What is (a) total mass of the box (b) the difference in masses of gold pieces to correct significant figures.

Answer 1

Here is your Answer:-

Mass of box = 2.3 Kg

$Mass \: of \: 1 ^{st} \: piece \: = 20.15g \: = \: \frac{20.15}{1000} = 0.02015kg$

$Mass \: of \: 2 ^{nd} \: piece \: = 20.17g \: = \: 0.02017 \: kg$

$\:Total \: Mass \: = \: 2.3 \: + \: 0.02015 \: + \: 0.0201 \\ = \: 2.32032 \: kg \\ = 2.3 \: kg$

Now,

$Difference \: of \: mass \: = 20.17 \: - \: 20.15 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \: 0.02 \: g$