Topic Menu

Cyber-chess a chess instruction site

Materials: Density

Q2. Jess measured the width of a solid metal cube using a digital micrometer.

The diagram shows the micrometer. The resolution of the micrometer is 0.01 mm

 

(a) Jess could have used a metre rule to measure the width of the cube.

Explain how using a metre rule would have affected the accuracy of the her measurement of the width.

The metre rule has a lower resolution so the reading taken would be less accurate than the micrometer screw gauge.

[2 marks]

(b) The mass of the metal cube was measured using a top pan balance.

The balance had a zero error.

Explain how the zero error may be corrected after readings had been taken from the balance.

You need to record the value of the zero error when there is no object on the balance. Then subtract the value of the zero error to your reading (if it reads more than zero) or add it on if it reads less than zero.

[2 marks]

(c) The width of the cube was 18.45 mm.

The density of the cube was 8.0 × 103 kg/m3

Calculate the mass of the cube.

ρ = m/V

m = V ρ

V = (18.45 x 10-3)3 = 6.280 x 10-6

m = 6.280 x 10-6 x 8.0 × 103

m = 5.0 x 10-2 kg

m = 0.05 kg

m = 50 g

The density is only given to 2 significant figures therefore your answer should be given to that number of sig figs - whereas the volue should be given to 4 sig figs as the cube width is read to that number of sig figs.

[5 marks]

[Total: 9 marks]