A hydrometer is an instrument used to determine liquid density. The bulb of a sy

Question

A hydrometer is an instrument used to determine liquid density. The bulb of a syringe is squeezed and released to let the atmosphere lift a sample of the liquid of interest into a tube containing a calibrated rod of known density. The rod, of length L and average density ?0, floats partially immersed in the liquid of density ?. A length h of the rod protrudes above the surface of the liquid. Show that the density of the liquid is given by: ? = ?0L/L ? h Please explain all step in detail. This is a question on a practice exam so i may be tested on this and need to know all detailed steps. Thank you!

Explanation / Answer

When the rod floats, the weight of the displaced fluid equals the weight of the rod.

fgVdisplaced=ogVrod-------1

But, assuming a cylindrical rod

Vrod =r2L

The volume of fluid displaced is the same as the volume of the rod that is submerged.

Vdisplaced =r2(L-h)

from 1

f*r2(L-h) =o*r2L

f =o[L/(L-h)]

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.