First slide

Fluid statics

Question

A piece of brass (Cu and Zn) weighs 12.9 g in air. When completely immersed in water, it weighs 11.3g. Then relative densities of Cu and Zn are 8.9 and 7.1 respectively. The mass of copper in the alloy is

Moderate

A

4.6 g
B

5.6 g
C

7.6 g
D

8.6 g

Solution

Loss of weight (12.9 - 11.3) gf = 1.6 gf
Weight of water dispalced = 1.6 gf
If m is the mass of Cu, then
$[\frac{m}{8.9} + \frac{12.9 - m}{7.1}] g = 1.6 g$
or 7.1 m + 12.9 x8.9 -8.9m = 1.6 x 8.9 x7.1
or 1.8m = 114.8 - 101.1
or m = 7.6 gram

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App