Given:
Mass of the box = 2.30 kg
Mass of first gold piece = 20.15 g
Mass of second gold piece = 20.17 g
(a) Total mass of the box
First, convert masses of gold pieces into kilograms:
20.15 g = 0.02015 kg
20.17 g = 0.02017 kg
Total mass added:
0.02015 + 0.02017 = 0.04032 kg
Now add this to the mass of the box:
Total mass = 2.30 + 0.04032 = 2.34032 kg
The mass of the box is given correct to two decimal places.
Hence, the final answer must be rounded to two decimal places:
Total mass of the box = 2.34 kg
(b) Difference in the masses of the two gold pieces
Difference = 20.17 g − 20.15 g = 0.02 g
Both masses are measured correct to two decimal places.
Hence, the difference should also be reported to two decimal places.
Difference in masses = 0.02 g
Final Answers:
(a) Total mass of the box = 2.34 kg
(b) Difference in the masses of the gold pieces = 0.02 g