Physics question about specific gravity?

G

goofy

New member
Can someone tell me step by step how to do this?

An unknown solid substance has weight 142.0 N. the object is suspended from a scale and hung so that it is completely submerged in water, but does not touch the bottom. the scale now reads 129.4

What is the specific gravity of the object?
 
As per Archimedes principle:

Wt of water displaced = Byuoant force

142- 129.4 = m_water X 9.8
12.6/9.8 = m_water
m_water= 1.2857 kg

Vol of water displaced = Vol of object
m_water / d_water = Vobject
1.2857/ 1000 = Vobject

Do= Mobject / Vobject = (142/9.8) * 1000/1.2857 = 11270 kg/m^3

Sp gravity = 11270/1000

~ 11.3
 
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