Question

A block of stone of mass 30 kg (S. G. 5) hangs from a cord and is completely immersed in water. Find the tension in the cord

Answer 1

Question :-

A block of stone of mass 30 kg (specific gravity = 5) hangs from a cord and is completely immersed in water. Find the tension in the cord (g = 10 m / s²).

Answer:-

$\Large\boxed{\sf{240\ N}}$

Solution:-

The tension in the string is equal to the weight of the block in water.

$\longrightarrow\sf{T=mg-U}$

$\longrightarrow\sf{T=300-U}$

But specific gravity,

$\longrightarrow\sf{\sigma=\dfrac{Weight\ of\ the\ body}{Weight\ of\ the\ displaced\ liquid\ (Upthrust)}}$

$\longrightarrow\sf{5=\dfrac{mg}{U}}$

$\longrightarrow\sf{U=\dfrac{mg}{5}}$

$\longrightarrow\sf{U=60\ N}$

Therefore,

$\longrightarrow\sf{T=300 - 60}$

$\longrightarrow\sf{\underline{\underline{T=240\ N}}}$