Advertisements
Advertisements
Question
A metal cube of edge 5 cm and density 9 g cm-3 is suspended by a thread so as to be completely immersed in a liquid of density 1.2 g cm-3. Find the tension in thread. (Take g = 10 m s-2)
Advertisements
Solution
Given, side of the cube = 5 cm
∴ volume of the cube = 5 × 5 × 5 = 125 cm3
Density of metal = 9.0 g cm-3
Density of liquid = 1.2 g cm-3
Mass of the cube = volume × density
= 125 × 9 = 1125 g
∴ weight of the cube = 1125 gf (downwards)
Upthrust on cube = weight of the liquid displaced
= volume of the cube × density of liquid × g
= 125 × 1.2 ×
= 150 gf (upwards)
Tension in thread = Net downward force
= Weight of cube - Upthrust on cube
= 1125 − 150
= 975 kgf
= 9.75 N ...[∵ g = 10 m s-2]
Hence, tension in thread = 9.75 N
APPEARS IN
RELATED QUESTIONS
Complete the following sentence.
Density in kg m-3 = ............ × density in g cm-3
What is the unit of relative density?
Calculate the mass of a body whose volume is 2 m3 and relative density is 0.52.
A body of volume 100 cm3 weighs 1 kgf in air. Find:
- Its weight in water and
- Its relative density.
A stone of density 3000 kgm3 is lying submerged in water of density 1000 kgm3. If the mass of stone in air is 150 kg, calculate the force required to lift the stone. [g = 10 ms2]
A solid weighs 0.08 kgf in air and 0.065 kgf in water. Find
(1) R.D. of solid
(2) Density of solid in SI system. [Density of water = 1000 kgm3]
A solid of R.D. = 2.5 is found to weigh 0.120 kgf in water. Find the wt. of solid in air.
An aluminium cube of side 5 cm and RD. 2.7 is suspended by a thread in alcohol of relative density 0.80. Find the tension in thread.
A cylinder made of copper and aluminium floats in mercury of density 13.6 gem-3, such that 0.26th part of it is below mercury. Find the density of solid.
An iceberg floats in sea water of density 1.17 g cm 3, such that 2/9 of its volume is above sea water. Find the density of iceberg.
